If you don't have her yet but want to try her out, she is available as a Trial Operative in Story Mission 7-12
Powercreep has meant that Coronet isn't a powerhouse of dps anymore, but she still provides good damage with strong parts break in a fun package, plus decent utility as a support operative as well.
Role: Main DPS w/ good Parts Break
Support - RoF buffs w/optional Parts Break
Deals Electric Damage
Deals ballistic damage
Mobility is decent
Good damage
Strong Parts Break
Pretty good as a support operative
DPS not exactly great by modern standards
We don't much care for Parts Break these days
Not a great support these days either
Parts Break doesn't come close to Agave
1. Spam her ultimate skill off-cooldown
2. Spam her standard skill off-cooldown
3. Otherwise, just shoot stuff
1. Spam her support skill off-cooldown
2. If Parts Break is needed, swap Coronet in, Parts Break, and then swap her back after.
Standard Attack and Passive Effect
Coronets standard attack is just a regular shotgun attack.
Her Deiwos does give her a 25% chance of an extra shotgun pellet.
Her ideal weapon is Sunny Payack, which can also give extra shotgun pellets.
These mean that Coronet tends to fire more shotgun pellets than other shotugn users, and thus she benefits more from per-shot effects, as those trigger for each pellet.
(For example the aptitude buffs of Phantasia and Little Sunshine.)
Standard Skill
Her Standard Skill gives her 80 Mercy point.
Each point of Mercy increases her Rate-of-Fire by 1%.
Mercy slowly ticks down over time, but each shot that Coronet hits gives her and extra 1.2 Mercy.
This skill lasts 12 seconds, or until Coronet runs out of Mercy, whichever comes first.
Whilst in this state, Coronet deals less damage to destructible parts and gains less U-Energy.
Ultimate Skill
Coronet deals PBAoE Electrical damage every 2 seconds.
This skill deals decent AoE damage to groups, but it's still a pretty weak skill.
If you have a decent support operative to suppot Coronet with, then you're almost certainly better off using your U-Energy for them rather than Coronet.
Support Skill
Coronet's Support Skill increases the RoF of the deployed operative by 30% for 8 seconds, or 10 seconds with her Neuronic.
Given that it has a 20s cooldown, the base uptime of this skill is 50%, but with some Skill Haste mods on her Logistics she can get much higher uptime.
Coronet wants an electrical shotgun, limiting her to basically two main options:
Sunny Payback
A strong Electrical Shotgun.
Extra pellets = Extra damage.
Discordance
A good Electrical Shotgun that gives extra Electrical DMG.
Sunny Payback is Coronet's best weapon.
If you don't have that you should use Discordance
Ambergris
Weaker than Discordance, but since it's an electrical shotgun it's still a good choice for Coronet should you not have Sunny Payback or Discordance
If you don't have any of those, just use Malbec - the 3* electrical shotgun she comes with by-default.
Alternatively, use any high-level shotgun until you can get a 4* or 5* electrical shotgun.
For Weapon Parts just go max ATK.
For stats you want +10.0% ATK and +10.6% Crit Damage.
For the Special talent, you want 8.5% Electrical Damage
Coronet has both a low base crit damage stat (30%) and a high crit chance( 25% from her shotgun, 28% from her Deiwos, and 12% from her Alignment Index = 65%)
(Remember that shots against enemy weakspots have a 100% crit chance, meaning any extra crit rate mods she has are literally worthless when shooting a weakspot.)
This means that Crit DMG Amplifier mods work out to be her strongest damage increase
With that being said, Crit Rate and Alignment Index mods do work out only slightly worse:
119.5% Damage factoring in crits, but with no Alignment Index, Crit Rate, or Crit DMG Amplifier mods
123.32% Damage with 3 max-roll Alignment Index mods
124.27% Damage with 3 max-roll Crit Rate mods
125.7% Damage with 3 max-roll Crit DMG Amplifier mods
Again, Alignment and Crit Rate mods are useless if shooting at a weakspot, but Crit DMG Amplifier mods are her best option regardless of what she's shooting at.
This means that whilst a Crit DMG Amplifier mod is Coronet's best stat after ATK, Crit Rate and Alignment Index are both very good stats that perform very similarly.
Note that if using Nightglow as a support, then Crit DMG Amplifier mods are stronger, due to Yao's strong crit dmg buffs.
Being one of the OG 5* operatives, Coronet doesn't have her own designated logistics squad:
Amano-Iwato
Increases ADS Ballistic DMG by 10% after a crit. Max 5 Stacks. A great choice if you are ADS'ing with Coronet due to her very high crit chance.
If you only hipfire and if you don't ADS then it's obviously terrible, but Coronets high crit rate gives Amano-Iwato great synergy with her.
Mingyi
When dealing Electrical DMG, increases ATK of the equipping operative by 1% for 3 sec. Max 45 stacks. Repeated triggers will reset the duration.
Still less total damage increase than Amano-Iwato, but doesn't need ADS, although does require Coronet fire basically continuously.
With higher Manifestations, Coronet's high uptime on her RoF-boosting standard skill means that sustaining Mingyi isn't overly difficult for her.
TL:DR: Use Amano-Iwato if you ADS, and Mingyi if not.
M1 removes the timer from her standard skill, and it now just expires when she runs out of Mercy.
Given that she can sustain the timer for quite a long period due to her shots gaining Mercy, this is actually quite a nice buff.
M2 increases the amount of Mercy each shot grants when under her standard skill from 1.2 to 1.7
This only works if she has an electrical weapon, but if you've gotten her to M2 then you should have already gotten one for her.
This is quite a large increase, and thus allows her standard skill to be used for a lot longer.
As long as you don't miss or get interrupted too much, M2 allows you to generally stay at max Mercy without too much issue.
M3 removes the Mercy cap (by-default 80) allowing Fenny to stack Mercy even higher.
Whilst there is no dps benefit to stacking Mercy higher, it does give her a longer grace period and allow her longer downtime
This is thus both a nice QoL change as well as being a technical uptime buff for her standard skill
In practice this is often a small or tiny buff though.
M4 gives Fenny's standard skill +1 level, increasing the RoF bonus Mercy gives from 1% to 1.05% per Mercy.
Going from 1% to 1.05% gives Coronet an additive RoF increase of 4% (I.e. 180% -> 184%)
M5 gives Fenny +15% Electrical damage whenever she has 80 or more Mercy.
This will happen a lot of the time in combat, and thus this is a nice damage increase, although sadly it's not a Final DMG mod and is just a regular Electrical DMG mod.
If you want efficiency (good damage with minimal investment), then M2 is a good stopping point.
If you can stack Mercy or keep it at or near-max, then M3 is instead an efficient stopping point.
Coronet wants Electrical, Ballistic, and ATK buffs:
Nightglow
Coronet can make full use of Nightglow's ATK, Ballistic, and crit buffs, and Nightglow is a fantastic support for Coronet.
Note that Nightglow is on-element to Coronet (Nightglow deals Electrical damage)
Coronets high crit rate means that Nightglow is generally Coronetsbest support as coronet gets a lot of use from Yao's Crit Dmg debuff.
This is especially true if Coronet has Crit DMG Amplifier mods on her logistics.
Vidya - Celestial Swan (and other resistance shredders)
Celestial Swan and other resistance shredders (Acacia - Kaguya, etc.) that reduce the enemies resistance help enemies take more damage.
If using Celestial Swan, make sure the other support isn't off-element to Coronet.
Eatchel - The Cub
A Blitzing Fangs M1 Eatchel provides healing as well as a decent ATK buff.
Not the strongest support, but still good.
Mauxir - Shadow Ka
Shadow Ka is quite nice against highly mobile targets (e.g. Esther) but even when her utility isn't needed her extra damage is very nice.
Note that Shadow Ka is off-element to Wednesday (Shadow Ka deals Chaos damage)
Tess - Phantasia
Extra damage per pellet adds a lot for Coronet due to her shotgun shooting 8 pellets, 1 more from Coronets passive, and Sunny Payback having an extra one too.
Fritia - Little Sunshine
The cope version of Phantasia.
Little Sunshine also adds Thermal dmg per shot, although much less than Phantasia.
Coronets best supports are Nightglow and Celestial Swan
Overall, Coronet is quite a strong DPS, a good Parts Break, and a competent support, all rolled into one.
Since she's available as part of the standard banner, you will get her eventually (and eventually max her) even if you don't explicitely try to pull for her.
Compared to modern DPS operatives though Coronet doesn't quite compare, but she does still perform very well despite her age, and has held up better than most of her standard-banner comrades.