Yojimbo, Masterless Guardian

At the beginning of your upkeep, pay {1}. If you
don't, tap Yojimbo.
{x}: Yojimbo gets +X/+X until end of turn
{2}{w/b}: Yojimbo gains vigilance until end of turn.
{4}{w/b}{w/b}: If Yojimbo has vigilance, exile all
creatures other than Yojimbo. Activate this
ability only as a sorcery