Summon Board Passive selections:
Numbers listed below refer to the 7 passives to select for each Ultimate Summon Board for the character. Top is 1, bottom is 7.Note: Neon enables rainbows for herself and allies. Any ATK/BRV DMG Boosting passives can be switched out if the summon offers more useful such as mBRV/Break Bonus/Resists/etc.
Ifrit 3 / 4 / 7
Odin choose 4 / 6 / 7
Bahamut choose 3 / 5 / 6
Usuals:
Shiva, Ramuh, Brothers 4 / 5 / 7
Leviathan, Pandemonium, Diabolos, Alexander 4 / 5 / 6
For more details and help with summons, check Summon Hub!
A Spheres - She gets rainbows, she doesn't need ATK/BRV DMG. These don't really matter.
E Sphere - Same as above, give her an aura debuff orb or whichever E sphere you have laying around.
Tl;dr: keep her debuff stacks above 5 (which she needs LD for). Her ability to provide party rainbow damage requires the ally to hit fire, so make sure you have a source of fire enchant (Neon's AA/BT effect or calls). Her debuff fails in the face of enemies that absorb fire, however that rarely happens so have fun!
Neon herself can maintain the stacks with her skills, however any other ally attacking an enemy with the debuff will lower it's stacks, even in BT phase (unless her BT effect is active, then they stay put)!
Neon can be played either as a BRV DMG support and or a consecutive turn damage dealer. Just be mindful of her overhead, how many turns she takes, her stacks and your source of Fire Enchant for allies.
Asura (S1) focuses on a single target, increases stacks by 2 and refreshes the debuff duration to 6T. With elemental weakness she will raise the stacks by 2 more.
Inferno (S2) refreshes her overhead, applies 3 stacks to all enemies and deals damage to all enemies.
Sword of Fury (EX) increases stacks to all enemies, provides 2 free skills and is an instant turn. It refills with 3 S1 uses meaning she can spam S1 3 times after EX and only eat up 1 skill use of it in situations you need to take turns to stall for a break or hog FR time to prevent a dragoon from landing or something. Doing it too much also risks dropping her overhead effect.
Fiend of Fire (LD) is mainly single target but has a splash HP attack at the end. The important part besides damage is it also sets her debuff to 10 stacks on every enemy.
Even if her debuff stacks fall below 6, she can push them up again after that first LD use. If enemies remove the buff, she will have to use LD again to unlock 10 max stacks.
Firebringer (BT) provides the party with True Fire Enchant (like Lulu LDCA), BRV DMG Limit Up, OF (stolen) up, HP DMG & Limit up along with preventing her debuff from lowering on allied turns.
Her BT Phase depends on enemies:
ST : EX -> S1 -> S1 -> S1 -> LD -> FR -> Finisher
2+ : S2 -> S2 -> EX -> S2 -> S2 -> FR -> Finisher (EX before phase)
LD -> EX -> S2 -> S2 -> S2 -> FR -> Finisher (No EX before phase)
Double Runic (FR) inflicts 5 stacks of her debuff and asks for:
Fire BRV DMG on turn (20%)
Deal 9,999+ BRV DMG in a single BRV hit (30%)
Attack a target with a stacking debuff (20%)
All of which Neon can easily enable and hit herself!
While her BT effect prevents her debuff from lowering on allied turns, it will still lower stacks on enemy turns meaning she wants aggressive teams/allies such as link attackers or other aggressive damage dealers with FR echo.
Two linked attackers pair especially well with Neon as she can take many turns and deal plenty of damage to be the spearhead of the party while her allies help melt HP in the background.
She can serve a supportive role with her debuff and BT effect enabling BRV DMG-reliant allies. This includes calls that drop a trap effect which can make up for some extra damage in some situations. On top of her BRV DMG support, other BRV gain calls/allies can ensure HP damage limit is reached on attacks for herself and the entire party during a strong BT phase from any ally.