Riku, Half of a Whole

First strike, hexproof, haste
Whenever you cast an instant or sorcery spell, draw a card. Then, you may pay {u/r}{u/r}. If you do, copy that spell. You may choose new targets for the copy.
Whenever Riku, Half of a Whole deals combat damage to a player, add {u/r} to your mana pool. (This mana won't empty from your mana pool between steps.)
{u/r}, Remove a +1/+1 counter from a creature you control: Draw a card.