Mayhem Devil

Whenever a player sacrifices a permanent, Mayhem Devil deals 1 damage to any target.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Rakdos Signet

Command Tower

Mirkwood Bats

Flying
Whenever you create or sacrifice a token, each opponent loses 1 life.

Juri, Master of the Revue

Whenever you sacrifice a permanent, put a +1/+1 counter on Juri, Master of the Revue.
When Juri dies, it deals damage equal to its power to any target.