Ophelia

Weapon: Missiletainn

Assist: Positional Assist / Flexible

Special: Blazing Wind / Flexible

IVs: +Atk / -HP or -Spd or -Def or -Res

Passive A: Life and Death 4 / Life and Death 3

Passive B: Special Spiral / Windsweep

Passive C: Time’s Pulse / Savage Blow / Flexible

Sacred Seal: Life and Death 3 / Initiate Seal Atk 3 / Hardy Bearing

• While Missiletainn lacks the sheer power of some newer weapons, it is still incredibly reliable and allows Ophelia to charge and unleash Specials easily. A 4-cooldown Special like Blazing Wind gets reduced to 3 by Missiletainn. At the start of turn 1, Ophelia will reduce its charge by 1 for each Tome user on her team, including herself. With three tomes, she will charge it immediately. With two, she needs an extra Pulse of some kind to get it fully charged; this can be achieved by an ally with higher HP and Infantry Pulse, or by using Time’s Pulse on Ophelia herself. 
• Once Blazing Wind is charged, it will activate before any combat Ophelia initiates, targeting her foe and any foe adjacent to them and dealing damage equal to 1.5 times the difference between her out-of-combat Atk and their out-of-combat Res. Because this damage calculation references visible stats and ignores in-combat stat boosts, skills like Life and Death are preferred in order to increase Ophelia’s visible Atk. Likewise, effects like Chill Res or Sabotage Res on Ophelia’s allies can increase her damage by reducing enemy Res. 
• After Blazing Wind hits, Ophelia attacks the weakened enemy in combat. Unless the enemy is using a skill such as Guard or Sturdy Stance 3 to slow her Special charge, she will gain 1 Special charge from this. By using Special Spiral, she will gain an additional 2 Special charge after combat, fully charging her Special again for the next combat. 
• Blazing Wind is generally the best choice of Special due to its shape, but other Blazing Specials such as Blazing Thunder or Blazing Flame may be better choices depending on the battle mode Ophelia is being used in, as enemy teams tend to cluster in different arrangements depending on the mode. 
• Hardy Bearing seal can be used instead of Life and Death in order to prevent Vantage effects from enemy units, though this will decrease Ophelia’s damage somewhat. Likewise, Windsweep can be used instead of Special Spiral in order to prevent counterattacks from physical units slower than Ophelia in modes where combats after her first are less important, such as Aether Raids Defense. 
• If Time’s Pulse is not needed for the C skill, Ophelia benefits from a variety of different C skills depending on the mode she is used in. Savage Blow is a solid choice to deal slightly more damage to nearby foes and make it easier for her to KO them in later combats, while Pulse Smoke can disable charged enemy Specials, including those like Aegis which would reduce Ophelia’s damage. Attack buffs from skills like Atk/Spd Oath or Joint Hone Atk increase Ophelia’s Special damage further, but she can also receive these from teammates using skills like Atk Tactic. There are many other options that can excel in different contexts. 

Weapon: Missiletainn

Assist: Positional Assist / Flexible

Special: Luna / Draconic Aura / Blue Flame / Flexible

IVs: +Atk / -HP or -Def or -Res

Passive A: Atk/Spd Ideal 4 / Death Blow 4 / Flexible

Passive B: Special Spiral

Passive C: Time’s Pulse / Savage Blow / Joint Drive Atk / Flexible

Sacred Seal: Blade Session / Flexible

• This build is similar to the previous build, except that it uses in-combat Specials instead of Area-of-Effect Specials. This is generally a weaker option, but also lacks some of the particular weaknesses of the AoE build, such as the vulnerability to skills like Mirror Stance 3 that can disrupt Ophelia’s Special charge after combat. With a 3-cooldown Special like Luna, Missiletainn reduces its cooldown further to 2, so Special Spiral charges it fully again after every combat in which it activates. 
• Any Ideal skill with Atk provides the largest reliable boost to Ophelia’s Atk, up to 9 if she is both at 100% HP and under the effect of any visible status buff (whether that be a buff to a stat like Atk or another status effect like Bonus Doubler from Legendary Eliwood). So Atk/Spd Ideal, Atk/Def Ideal, and Atk/Res Ideal all work, with Atk/Spd being arguably the best choice as the Spd may reduce the damage reduction Ophelia’s foe receives from a skill like Close Call. 
• Likewise, Blade Session provides the largest possible boost to Atk from a seal, up to +9 if two of Ophelia’s allies are present on the map and have ended their turn before her action. 
• The particular choice of Special is flexible, with no clear best option. Luna provides a larger power boost the more Res Ophelia’s foe has, which is generally helpful. Blue Flame provides a flat +25 damage if Ophelia is adjacent to an ally when she initiates combat, or +10 if she is not. Draconic Aura provides a boost equal to 30% of Ophelia’s Atk, which will usually be around 18-22 extra damage most of the time. It is generally a weaker option than Luna but may be worthwhile against foes with high HP and low Res.