Weilao, Twinspell Master

Whenever you cast a blue instant spell, you may
exile that card as it resolves if another blue card
is not already exiled by Weilao.
Whenever you cast a red instant spell, you may
exile that card as it resolves if another red card
is not already exiled by Weilao.
You may cast cards exiled by Weilao.
When Weilao leaves the battlefield, put all cards
exiled by it into their owners' graveyards.