Character Card System

This is something minor, but you made a typo for Angelic buster. Should be buster instead of blessing xP.
Anyway, Kanna's card effect adds 1/2/3/4% boss damage and Hayato's card adds 2/4/6/8% minimum critical damage.
Seeing as how we'll probably get Demon Avenger (whose character card also gives boss damage) along with the other classes in the near future, think the effects from that and Kanna's card stack with each other?

I have a Merc as a main and thinking of submaining a revamped Wind Archer in the future. So I'm wondering if these sets would work?

[Set1]
Marksman (4% critical rate)
Mercedes (5% cooldown)
Wild Hunter / Wind Archer (instant kill /accuracy boost or filler)

3 archers for +3/4% damage to final attack skills. If I'm able to get the Wind Archer to Lv200, then I can use the rank SS effect.

[Set2]
Aran (70% Chance of healing of 6% HP)
Demon Slayer (3% Status resistance)
Hayato (6% minimum critical damage)

3 warriors for 8% HP to damage.

[Set3]
Battle Mage (4% damage reduction)
Xenon (+20 Str, Dex, Luk)
Demon Avenger (+3% boss damage)

Resistance set effect for +7 stats.