Altair, Brotherhood Mentor - Kelsien, the Plague (Rainbow Foil) (SLD-1558) - Secret Lair Drop Series Foil

Vigilance, haste

Altaïr, Brotherhood Mentor gets +1/+1 for each experience counter you have.

T: Altaïr deals 1 damage to target creature you don’t control. When that creature dies this turn, you get an experience counter.