Wizard from Beyond

Create a Character (Any nonlegendary creature can choose this as its Background. It becomes legendary and can be your commander.)
Commander creatures you own are Clerics, Rogues, Warriors, and Wizards in addition to their other types.
As long as you have a full party, if an ability of a creature you control triggers, that ability triggers an additional time.

Master of Cruelties

First strike, deathtouch
Master of Cruelties can only attack alone.
Whenever Master of Cruelties attacks a player and isn't blocked, that player's life total becomes 1. Master of Cruelties assigns no combat damage this combat.