Cain

• Preferred IV: +SPD or +ATK / -RES
• Weapon: Firesweep Sword+ / Brave Sword+
• Assist: Reposition / Draw Back
• Special: Luna
• Passive A: Swift Sparrow / Life and Death / Death Blow
• Passive B: Swordbreaker / Hit and Run / Drag Back
• Passive C: Hone Cavalry / Fortify Cavalry / Flexible
• Sacred Seal: Speed +3 / Attack +3

Cain's stats spread leans toward offense much more than defense. In a Cavalry Team, with Hone Cavalry buff he can reach a respectable 38 base Attack/Speed before boon/bane and skills, allowing him to be a decent Firesweep Sword or Brave Sword user.

This set is a standard offensive build for Player Phase-oriented units like Cain and the skill choices are fairly straightforward. Cain will want mainly Speed then Attack to facilitate his attacking role, thus skills that grant these two stats like Swift Sparrow or Life and Death are no-brainers on him.

Swordbreaker allows him to dispatch units like Ayra, Mia or Zelgius who would pose a major problem otherwise for him. Hit and Run and its weaker equivalent. Drag Back is also not a bad choice to keep him safe.

• Preferred IV: +SPD or +ATK / -RES
• Weapon: Slaying Edge+ (+Spd) / Wo Dao+ (+Spd) / Ruby Sword+
• Assist: Reposition
• Special: Moonbow
• Passive A: Distant Counter / Close Def / Fury
• Passive B: Swordbreaker / Quick Riposte / Guard
• Passive C: Hone Cavalry / Fortify Cavalry / Flexible
• Sacred Seal: Quick Riposte / Distant Def / Close Def

Cain can run a decent duelist set in Cavalry Team thanks to how immensely powerful Cavalry's buffs are. It is worth mentioning however alternatives like Sigurd, Xander or Eldigan would do a much better job. However, if you just want another to use Cain specifically then this build could work on him.

For the weapon, Slaying Edge is the best for general use, followed by Wo Dao. Ruby Sword is a lot more specialized toward checking Green and can remedy Cain's tankiness, but his use would be a lot more limited.

Cain's Attack isn't particularly great to use Glimmer, so Moonbow with Slaying Edge's reduced cooldown is best for him.

Distant Counter is the go-to premium choice for A slot for most Enemy Phase units. Outside of that, Cain can run various options including Close Def, Fury or Triangle Adept; all will help him tremendously in combat as his bulk is quite mediocre.

His B slot is dependent on which threats you want him to handle. Breaker skills are obviously specialized for this purpose, and Swordbreaker will give him the most values out of Breaker skills in general due to the prevalence of units like Ayra or Zelgius. Breaker + Quick Riposte for his Sacred Seal slot is a great combination to provide maximum coverage possible.

If you run Quick Riposte on him in his B slot, however, you can switch to Close Def or Distant Def for his Seal slot for more bulkiness depending on whether you use Distant Counter or not. Guard is another interesting choice that can go well with Quick Riposte Seal, allowing him to handle units with skills like Steady Breath, Bold Fighter or Vengeful Fighter a lot more effectively.