In-Depth Guide To "Astral Reflection", Mona


Introduction

Official Description

A mysterious young astrologer who proclaims herself to be "Astrologist Mona Megistus," and who possesses abilities to match the title. Erudite, but prideful. Though she is often strapped for cash and lives a life of thrift, she is resolved to never use astrology for profit... It is this very resolution that has caused her to constantly fret about money.

In-game Profile

Teyvat is a place where people of all sorts go about their business. Merchants move product, knights patrol, and farmers till the land. But if one were to ask Mona - the enigmatic and prideful astrologist - what she busies herself with, she will reply by saying that she is servicing a debt known as "life." She will, however, vigorously deny being "poor," giving the following explanation: "Beautiful veneers may obscure simple truths. Exquisite food may mask its nutritional value. One lives simply, all the better to expose this world's truths." A frugal lifestyle, therefore, is a form of training to access the truth... Or so Mona will insist. Teyvat is a place where people of all sorts go about their business, and even an enigmatic astrologist must look to hers. - That said, it seems like bards might be the exception to this rule.


Exploring Mona's Abilities

Talents

 Talent TypeTalent NameTalent DescriptionThoughts
Normal/Charged AttackRipple of FateNormal Attack: Perform up to 5 water splash attacks that deal Hydro DMG.
 

Charged Attack: Consumes a certain amount of Stamina to deal AoE Hydro DMG after a short casting time.

Plunging Attack: Gathering the might of Hydro, Mona plunges towards the ground from mid-air, damaging all enemies in her path. Deals AoE Hydro DMG upon impact with the ground.

The damage scaling on Mona's normal attacks is bad, which is why for a DPS build, you want to be spamming charged attacks.
Elemental SkillMirror Reflection of DoomCreates an illusory Phantom of fate from coalesced waterspouts.
 

The Phantom has the following special properties:

  • Continuously taunts nearby enemies, attracting their fire.
  • Continuously deals Hydro DMG to nearby enemies.
  • When its duration expires, the Phantom explodes, dealing AoE Hydro DMG.

Hold: Utilizes water currents to move backwards swiftly before conjuring a Phantom

Only one Phantom created by Mirror Reflection of Doom can exist at any time.

Really nice skill for survival. In some cases, you could even drop your healer completely if you use this skill for its taunt properties. Though do note that only one phantom can exist at any time, so if you use Sacrifical Fragments on Mona, and get the cooldown before the phantom expires, there's not much point in recasting.
Alternate SprintIllusory TorrentAlternate Sprint: Mona cloaks herself within the water's flow, consuming stamina to move rapidly.
 

When under the effect of Illusory Torrent, Mona can move at high speed on water.
Applies the Wet status to nearby enemies when she reappears.

Really helps with exploration. You can also use this to move on water, and it also works to apply Hydro to a group of enemies.
Elemental BurstStellaris PhantasmMona summons the sparkling waves and creates a reflection of the starry sky, applying the Illusory Bubble status to the opponents in a large AoE.
 

Illusory Bubble: Traps opponents inside a pocket of destiny and also makes them Wet. Renders weaker opponents immobile. When an opponent affected by Illusory Bubble sustains DMG, the following effects are produces:

  • Applies an Omen to the opponent, which gives a DMG Bonus, also increasing the DMG of the attack that causes it.
  • Removes the Illusory Bubble, dealing Hydro Elemental DMG in the process. The DMG Bonus does not apply to the Hydro Elemental DMG dealt in this instance.

Omen: During its duration, increases DMG taken by enemies.

This is an overpowered skill that you want to spam as often as possible. We'll be talking about it in detail in a later section.
Passive Talent 1Come 'n' Get Me, Hag!After she has used Illusory Torrent for 2s, if there are any enemies nearby, Mona will automatically create a Phantom.

A Phantom created in this manner lasts for 2s, and its explosion DMG is equal to 50% of Mirror Reflection of Doom.

You can use this talent right after the Phantom from your elemental skill disappears, since the more the Phantom is present on the field, the higher your survivalability is because of its taunting, in addition to the damage.
Passive Talent 2Waterborne DestinyIncreases Mona's Hydro DMG Bonus by a degree equivalent to 20% of her Energy Recharge rate.This is a very important talent that we'll be building on.
Passive Talent 3Principium of AstrologyWhen Mona crafts Weapon Ascension Materials, she has a 25% chance to refund a portion of the crafting materials used.No biggie.

Constellations

 LevelNameOfficial Description
1Prophecy of SubmersionThe effects of Hydro-related Elemental Reactions are enhanced for 8s after any of your characters in the party hit an enemy affected by an Omen:
  • Electro-Charged DMG is increased by 15%.
  • Vaporize DMG is increased by 15%.
  • Hydro Swirl DMG is increased by 15%.
  • The duration for which enemies are Frozen is increased by 15%
2Lunar ChainWhen a Normal Attack hits, there is a 20% chance that it will be automatically followed by a Charged Attack. This effect can only occur once every 5s.
3Restless RevolutionIncreases the Level of Stellaris Phantasm by 3. Maximum upgrade level is 15.
4Prophecy of OblivionWhen any character in the party attacks an enemy affected by the Omen status effect, their CRIT Rate is increased by 15%.
5Mockery of FortunaIncrease the Level of Mirror Reflection of Doom by 3. Maximum upgrade level is 15.
6Rhetorics of CalamitasUpon entering Illusory Torrent, Mona gains a 60% increase to the DMG her next Charged Attack per second of movement. A maximum DMG Bonus of 180% can be achieved in this manner. The effect lasts for no more than 8s.

Diving Into Mona

How does Mona work?

Mona is mostly used as a CC spammer, meaning she depends on her elemental skill and burst a lot for her damage. For Mona, the most important thing is Stellaris Phantasm; The damage achievable by this skill is no joke, which is why you want to aim to have it available as much as possible, which is why we build Mona for Energy Recharge. Luckily, this does not only help her burst's uptime, but also increases her Hydro DMG through her second passive talent. We need to deeply understand how Stellaris Phantasm works to maximize Mona's potential.

Stellaris Phantasm

This skill is broken with the insane amount of damage and crowd control (through its big range) you can achieve with it, but you need to learn how to unlock its potential. This skill really shines with a pyro character to trigger Vaporize, but there's a catch. You need to know how Stellaris Phantasm works for this. On cast, this skill will engulf enemies in a "bubble", and apply Hydro the "Omen" status to them (which is a big source of damage bonus for attacks), giving a damage bonus to attacks. After some time, the bubble will automatically burst, dealing a large amount of Hydro damage (Do note that this damage is not affected by the Omen status damage bonus). During the duration of the burst, small enemies will be trapped in that bubble and be unable to move, while larger enemies will still have the "bubble" effect on them (the Omen status and the damage of the bubble burst) but will still be able to move. You can also burst the bubble yourself by hitting it, and the burst damage will happen right after the hit. There are two important things here to note for maximizing this skill's potential. First is that this skill applies Hydro on cast, and the bubble burst is also Hydro damage. This means that if you simply cast the burst, and switch to a Pyro character and use a skill to trigger Vaporize, the damage will be purely Hydro and the reaction will not happen.

Why does this happen? Remember, the burst applies Hydro. When you hit with your Pyro skill, Hydro is already on the enemy, which will react with your skill and trigger Vaporize, but also remember that the bubble burst damage happens right after the hit; By the time the burst damage happens, Pyro had already reacted with Hydro, and no element is currently applied on the enemy to react with since those elements cancel out each other on reaction.

What should we do then? Apply Pyro before casting the burst. This is so that the Hydro application of the cast will cancel out with the Pyro first. No elemental status will be on the enemy, and when you use your Pyro skill, you apply Pyro, and immediately after that the bubble bursts, and triggers Vaporize with its reaction damage.

There's also a catch here: Mona is the one triggering the elemental reaction, meaning that its damage will scale off her stats, not the Pyro character's. This means that you do not need a high level Pyro character at all, as a level 1 will do since all we need is Pyro application and since elemental reaction damage only scales off the stats of the character triggering the reaction. In addition, this is an ideal situation, because Vaporize is one of the special reactions that get a damage multiplier, and that multiplier is 2x if the reaction is triggered by the Hydro element, and 1.5x if triggered by the Pyro character. This is why we want Mona to be the one triggering Vaporize. Moreover, unlike other reactions beside Melt, Vaporize doesn't scale only off Elemental Mastery and character level; it accounts for ATK, CRIT, Elemental DMG bonuses etc, and all of these stats are obtainable through artifacts and weapons, which is why to maximize Mona's damage, we want to always be triggering Vaporize with her since it scales off many more factors than other reactions, hence more damage.

One more thing: To achieve the highest damage possible out of the bubble burst, you'll need to wait a little bit before bursting the bubble for the ICD of Mona's Hydro application.

TL;DR Apply Pyro, cast Stellaris Phantasm, wait ~3 seconds, use Pyro skill = Absurd Hydro damage.

What constellations are worth aiming for?

What are the chances of you having a Mona, or any 5-star constellation for that matter? Not very high. You don't have to fret about this. Mona does NOT need any constellations to be the insane support she is; In fact, for a support build, only her 1st, 3rd and 4th constellations are worth it (3rd for Stellaris Phantasm levels, 4th for CRIT Rate for other party members). Her first constellation is amazing, as it will increase the damage you deal with Vaporize through your burst on other enemies once you pop a bubble. You could also cast Mona's elemental skill right after you burst the bubbles, so that it constantly applies Hydro, then switch to other characters and trigger reactions.

If you are building Mona as a DPS character, only her 6th constellation really boosts her damage. Her second constellation is not worth it because Mona's normal attacks have bad scaling anyway, so you should be spamming charged attacks with her if you build her as DPS (In fact, this constellation effect has a 20% chance of being triggered, and during the time you try to trigger it with your low damage normal attacks, you might as well just use charged attacks instead).

Talent upgrades?

Whether you're building Mona as a DPS or a support, maxing out Stellaris Phantasm comes first (That's just how absurd the damage from this skill is). After that, if you're building her as a DPS, you want to level up Ripple of Fate (Your normal/charged attacks talent) then your elemental skill (Mirror Reflection of Doom). If you're building her as a support, level up Mirror Reflection of Doom, since as a support, you'll only be casting her cooldowns then switching to other characters.

Building Mona

Note that while Mona has the potential to deal the highest amount of damage compared to other characters (A player achieved 1 million damage on Floor 7 with a Mona team), she is optimally played as a support character (and the high numbers are through a support build too), not as a DPS. This is because she doesn't have really good scaling for her normal attacks. You can only get some real damage with her charged attacks, which is what you would spam with a DPS build along with your abilities. Even then you will still need to rely on other characters, otherwise you will not be able to maximize Mona's potential.

DPS Build

Weapon Choice

 NameBase StatsPassive Effects (R1)Reasoning
The Widsith

Base ATK: 42

Sub-stat: CRIT DMG 12%

When a character takes the field, they will gain a random theme song for 10s. This can only occur once every 30s. Recitative: ATK is increased by 60/70/80/90/100%. Aria: Increases all Elemental DMG by 48/60/72/84/96%. Interlude: Elemental Mastery is increased by 240/300/360/420/480.

CRIT DMG sub-stat, which we can use in a DPS build because we'll be spamming normal and charged attacks. The passive is insane and gives very large boosts. 4-star book, so while it's still a gacha book, it's much easier to obtain and refine than 5-star weapons.
Skyward Atlas

Base ATK: 42

Sub-stat: ATK 7.2%

Increases Elemental DMG Bonus by 12%. Normal Attack hits have a 50% chance to earn the favor of the clouds. which actively seek out nearby opponents to attack for 15s, dealing 160% ATK DMG. Can only occur once every 30s.Big ATK% boosts which will increase all of Mona's damage, in addition to the elemental DMG bonus from its passive. The proc is also a nice source of damage. Depending on your stats, Skyward Atlas is comparable to Widsith, and probably even wins on R1. Widsith is much easier to refine though; With refinements, Widsith is the best choice for any Mona build.
Lost Prayers to the Sacred Winds

Base ATK: 46

Sub-stat: CRIT Rate 7.2%

Increases Movement Speed SPD by 10%. When in battle, earn a 6/8/10/12/14% Elemental DMG Bonus every 4s. Max 4 stacks. Lasts until the character falls or leaves combat.

5-star book, meaning it will give higher ATK stat, which will scale not only her skills and attacks, but also the damage from a Melt/Vaporize reaction. CRIT Rate sub-stat too which is great for a DPS build. The passive is also amazing as it will give a permanent 24% Hydro DMG at rank 1 which is huge.
Solar Pearl

Base ATK: 42

Sub-stat: CRIT Rate 6%

Normal Attack hits increase Elemental Skill and Elemental Burst DMG by 20/25/30/35/40% for 6s. Likewise, Elemental Skill or Elemental Burst hits increase Normal Attack DMG by 20/25/30/35/40% for 6s.

CRIT Rate sub-stat and big boosts to Mona's abilities through its passive.
Mappa Mare

Base ATK: 44

Sub-stat: Elemental Mastery 24

Triggering an Elemental reaction grants a 8/10/12/14/16% Elemental DMG Bonus for 10s. Max 2 stacks.With this book you want to trigger elemental reactions often so that you can keep the effect active. It also gives some Elemental Mastery, though has bad scaling with levels unlike books such as Sacrifical Fragments.

Artifact Choice

ArtifactsImportant Info/Reasoning
4-Piece Heart of DepthBest option for a DPS Mona due to its set bonuses that greatly benefit her DPS playstyle of spamming charged attacks, along with the Hydro DMG bonus which is ideal since all of Mona's damage is Hydro.

2-Piece Heart of Depth

2-Piece Gladiator's Finale

Hydro set ATK boost which will boost Mona's overall damage. and we're choosing Gladiator's over Noblesse here because you will be spending more time on Mona spamming her attacks, rather than using her burst and switching. The Noblesse set will only boost your burst damage, while the Gladiator's will boost all damage because it's an ATK increase. Wanderer's is also preferred over Noblesse with Gladiator's for a similar reason; You can trigger elemental reactions through more than your burst, giving you better damage output.

2-Piece Noblesse Oblige

2-Piece Gladiator's Finale/2-Piece Heart of Depth

Boost to Mona's elemental burst damage, and an overall boost to her damage through either the Hydro set or the Gladiator's ATK bonus. Hydro set is preferred here due to having a direct increase to damage, unlike ATK%.

2-Piece Wanderer's Troupe

2-Piece Noblesse Oblige

We want to make maximum usage of Mona's burst, which is still a lot of damage even without triggering Vaporize. This is why we have the 2-piece Noblesse set. We're also running the 2-piece Wanderer's because we still want to trigger reactions with Mona, especially with her burst.
4-Piece Wanderer's TroupeThe 4-piece set bonus will make spamming Mona's charged attack more valuable because of the damage increase.

For a DPS build, you want to get Hydro DMG Bonus on your goblet, CRIT on your circlet, and ATK% on your hourglass. The difference between a DPS build and a support build is that in a support build we focus much more on Energy Recharge, since our main source of damage on Mona would be her burst, so we would be looking at high burst uptime. But here we will spend a lot of time on Mona as a DPS, so we want to focus on ATK and CRIT stats. Energy Recharge is ideal alongside those stats on your artifacts' substats, because we'll still be using Mona's burst and getting a lot of damage out of it.

Support Build

Weapon Choice

 NameBase StatsPassive Effects (R1)Reasoning
The Widsith

Base ATK: 42

Sub-stat: CRIT DMG 12%

When a character takes the field, they will gain a random theme song for 10s. This can only occur once every 30s.Recitative: ATK is increased by 60/70/80/90/100%.Aria: Increases all Elemental DMG by 48/60/72/84/96%.Interlude: Elemental Mastery is increased by 240/300/360/420/480.Any of the 3 effects will greatly boost Mona's potential especialy with her burst. It's sub-stat is fine if you're running a Vaporize team comp which is what you should be doing with Mona, since Vaporize can crit. This is pretty much the best book for Mona as at level 80 it will give 50% CRIT DMG, which is insane. Though it is a bit harder to refine than Mappa Mare since it's a gacha book.
Mappa Mare

Base ATK: 44

Sub-stat: Elemental Mastery 24

Triggering an Elemental reaction grants a 8/10/12/14/16% Elemental DMG Bonus for 10s. Max 2 stacks.This is a great weapon for a support Mona. It has an Elemental Mastery sub-stat (though doesn't scale well with leveling, hence coming in second). To maximize Mona's burst damage, we want to have high Elemental Mastery on Mona to get a lot of damage out of the elemental reaction. In addition, the passive is really great to boost Mona's Hydro damage, which will further boost the damage from elemental reactions with her burst. 
Favonius Codex

Base ATK: 42

Sub-stat: Energy Recharge 10%

CRIT Hits have a 60/70/80/90/100% chance to generate a small amount of Elemental Particles, which will regenerate 6 Energy for the character. Can only occur once every 12/10.5/9/7.5/6s.We're only looking at this book for its Energy Recharge sub-stat. Late-game, Mona needs a lot of Energy Recharge, which is why we're considering this book.
Thrilling Tales of Dragon Slayers

Base ATK: 39

Sub-stat: HP 7.7%

When switching characters, the new character taking the field has their ATK increased by 24/30/36/42/48% for 10s. This effect can only occur once every 20s.This weapon's passive is the only thing that makes it worth using for Mona. It's a 3-star book which makes it easily refinable. The 48% ATK you get from this book at rank 5 is huge. Switch from Mona to your main DPS to give him this boost.
Sacrifical Fragments

Base ATK: 41

Sub-stat: Elemental Mastery 48

After damaging an opponent with an Elemental Skill, the skill has a 40/50/60/70/80% chance to end its own CD. Can only occur once every 30/26/22/18/14s.We're looking at this book only for its Elemental Mastery sub-stat. The passive isn't that valuable (though the skill is), as Mona's skill is a duration-based skill, making its cooldown not really that long in the first place, and only one phantom can exist on the field at any time, so there won't be much use from resetting the cooldown of the skill.

Artifact Choice

ArtifactsImportant Info/Reasoning

4-Piece Noblesse Oblige

OR

2-Piece Noblesse Oblige/2-Piece Wanderer's Troupe

2-Piece Heart of Depth

This will depend on the characters you have. If, for example, you have a support Bennet on your team, you can use the 4-Piece NO on him instead of Mona, and try to get a 2-Piece Wanderer's Troupe to boost her Elemental Mastery for more damage when popping her bubble (Highly recommended). Those are a support Mona's best options, due to providing great boosts to her burst (20% DMG through the 2-piece NO, 80 Elemental Mastery through the 2-piece Wanderer's Troupe, and both being 5-star sets). The new Hydro set will give bonus Hydro DMG for its 2-piece set, which will also boost all of Mona's damage.

2-Piece Noblesse Oblige

2-Piece Exile/Scholar

Exile/Scholar 2-piece sets will provide 20% Energy Recharge, which will help keep your burst up more often and boost your Hydro DMG through Mona's passive.

Ideally, you want Energy Recharge on the hourglass, Hydro DMG% on the goblet, and Elemental Mastery/CRIT on the circlet for a support Mona. Be aware that only vaporize/melt scales with CRIT; Other reactions such as Superconduct, Electro-charged etc only scale off Elemental Mastery and character level, which is why EM is recommended on Mona for a more well-rounded build, though note that the reaction damage from other reactions is not that good in the first place anyway, which is why some people might argue about EM vs CRIT on Mona. If you do end up getting a CRIT circlet, it's fine, that's really good. Just run a pyro character with Mona to trigger vaporize (which is what you want to do to maximize her potential anyway). Moreover, you will get roughly the same damage as CRIT with EM on vaporize/melt, so it's not that big of a deal. CRIT (Whether it's rate or DMG) is also highly recommended on your artifacts' substats, along with Energy Recharge, Elemental Mastery, ATK%. 200%+ Energy Recharge is ideal for Mona for high burst uptime, which is the most important thing with a support Mona. If you manage to achieve that without an Energy Recharge main stat hourglass, you can go for an ATK% one for more damage.

Team Comps

With a support Mona, you ideally want to have a Pyro element in your team so she can proc vaporize to deal a lot of damage. You can use Bennet here, who will also provide heals for you, though this could be your main DPS such as Diluc (Remember, you can also use other characters, these are just recommendations). The level of the character doesn't matter, as we just need it to inflict the Pyro status.

Other than having a Pyro character, it doesn't really matter what else you have, since that's all Mona needs. Hydro elemental resonance isn't that good, so it doesn't really matter that much if you have another Hydro character on the team, although note that it will boost your energy gain for Mona.

You might also want to test a team with and without a healer, as Mona's elemental skill will provide taunt which will reduce the damage you receive, so you might not need a healer.

Also, consider having an Anemo user such as Sucrose with a Viridescent Venerer set to reduce Hydro resistance, which will greatly boost Mona's damage. Inflict Hydro with Mona, swirl it, then start your Stellaris Phantasm combo (Inflict Pyro...). The range of Mona's burst is big, so you don't need to gather enemies in one place before bursting.

If you're runnnig Mona as your main DPS, you have the option of going with a Vaporize Comp, which relies on having Pyro on the enemies all the time and constantly proccing Vaporize with your Mona for the 2x DMG multiplier. For such a team, Bennet is a very good option for healing and Pyro application. You also really want an Anemo support like Sucrose or Venti here to constantly swirl Pyro while you spam your Hydro attacks. You also have the option to go with an Electro-charged Comp with characters like Fischl and Beidou being able to apply Electro off-field for your Mona to proc EC.