Obo'shi, Akuma Senshi

Ninjutsu {1}{b}{r}
Flying, trample, haste
You may pay ninjutsu costs with 3 life for each
mana you would spend instead.
Whenever a Obo'shi, Akuma Senshi deals damage
to a player, they sacrifice a Shrine they control. If
they can't, they discard a card instead.