This seems like a good card to have access to, but I dont think you want a playset, at least not main
Dropping him once you have an established board can get you very close to an instant ultimate, but dropping him early is still great, because he can make the way for your Ninjas to connect while giving you card advantage
No, you can only sacrifice creatures you control
Being that ninja decks can be a bit mana hungry, that cost reduction does a lot of work for us
It has great single-target removal spells like Path to Exile as well as a few sweepers like Time Wipe, and conditional cards like Dusk that help preserve a player's battlefield while wiping out an opponent's or two
It could definitely be a good thing to sink mana into in the late game, but its hard to know how useful thatll actually be