The most powerful card from Assassin's Creed is Yggdrasil, Rebirth Engine, which sees niche Modern and Legacy play, often as a one-of in Show and Tell decks in Legacy or as graveyard hate in Modern
Every non-token creature enters with a bonus counter, then lets you scale proliferate equal to your creature count
If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead. This is basically the perfect card for a Ghave, Guru of Spores deck, but it works in every +1/+1 counter deck too
In a normal game of Magic, this kind of one-for-one trade seems fine, but in this case, there are two other players at the table who spend zero cards on this exchange
Hand Kotis some weapons and evasion and it'll take a game over real fast