Infernal Kirin

Flying
Whenever you cast a Spirit or Arcane spell, target player reveals their hand and discards all cards with that spell's mana value.

King of the Oathbreakers

Flying
Whenever King of the Oathbreakers or another Spirit you control becomes the target of a spell, it phases out. (Treat it and anything attached to it as though they don't exist until your next turn.)
Whenever King of the Oathbreakers or another Spirit you control phases in, create a tapped 1/1 white Spirit creature token with flying.

Rend Flesh

Indebted Spirit

Bestow {2}{W} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached.)
Afterlife 1 (When this permanent is put into a graveyard from the battlefield, create a 1/1 white and black Spirit creature token with flying.)
Enchanted creature gets +1/+1 and has afterlife 1.

Skullmane Baku

Whenever you cast a Spirit or Arcane spell, you may put a ki counter on Skullmane Baku.
{1}, {T}, Remove X ki counters from Skullmane Baku: Target creature gets -X/-X until end of turn.

Celestial Kirin

Flying
Whenever you cast a Spirit or Arcane spell, destroy all permanents with that spell's mana value.