Mandalorian Super Commandos fought for Darth Maul following his takeover of Death Watch during The Clone Wars.
All good except for the fact that Darth Maul didn't die so Anakin would have been the first person to kill a Sith in all that time.
Darth Sidious & Darth Maul from The Clone Wars
Darth Maul & Savage Opress vs. Darth Sidious (gif) | Star Wars The Clone Wars "The Lawless"
"We are brothers. The true Lords of the Sith."
Darth Maul - Info, Pictures, and Videos | StarWars.com
'Star Wars: The Clone Wars' Season 5 trailer: Darth Maul, Death Watch battle over the galaxy -- EXCLUSIVE
Darth Maul Returns
Darth Maul by Marcus Whinney