Quest for the Holy Grail

Whenever a Knight you control attacks, you may
put a quest counter on Quest for the Holy Grail.

Remove twelve quest counters from Quest for the
Holy Grail and sacrifice it: Create Holy Grail, a legendary colorless artifact token with "At the
beginning of your upkeep, if you control three or
more legendary Knights, you win the game" and
"{t}: Target legendary creature you control gains protection from everything until end of turn."