Scathach or Fuuma?

Hey it all depends if you want a powerful Quick Team with low cost or the (best) waifu. With only 3 stars fuuma is really good at providing stars + support allies however he deals no damage compared to Scathach. Also you may find Shishou a bit strange as her skills are varied (maybe too much).
Well for my part i would say Shishou.

Fuuma - Star gen, enemy debuff.
Scathach - team utility, higher dmg/crit.
Tho scathach has one of the highest star gen percentages in game, and can generate a decent amount of stars if you smack her with elegant bastars and get an NPQQ chain with her.