Nefarox, Overlord of Grixis
{4}{B}{B}
Legendary Creature -- Demon
5/5
Flying
Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
Whenever ~this~ attacks alone, defending player sacrifices a creature of their choice.
Thraximundar
{4}{U}{B}{R}
Legendary Creature -- Zombie Assassin
6/6
Haste
Whenever ~this~ attacks, defending player sacrifices a creature of their choice.
Whenever a player sacrifices a creature, you may put a +1/+1 counter on ~this~.