Frostling

Enchant creature Enchanted creature has "Whenever this creature deals combat damage to a player, add that much G. Until end of turn, you don't lose this mana as steps and phases end."

Flying 2, Return a land you control to its owner's hand: Tap target land.

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

Whenever this creature attacks or blocks, you lose 1 life if you don't control a Demon.

The "legend rule" doesn't apply.

Defender (This creature can't attack.) Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.) T: The next time a source of your choice would deal damage this turn, that damage is dealt to Opal-Eye instead. 1W: Prevent the next 1 damage that would be dealt to Opal-Eye this turn.

Flying Creatures you control have "Whenever this creature becomes the target of a spell or ability for the first time each turn, counter that spell or ability."

Enchant creature Enchanted creature has flying. Sacrifice this Aura: Return enchanted creature to its owner's hand.