Brothers

Darth Maul and Savage Opress from Star Wars :The Clone Wars.

Savage Opress was a Dathomirian Zabrak Nightbrother who became a Sith Lord alongside his younger brother, Darth Maul, during the Clone Wars. Originally a tribal leader on Dathomir, Opress was handpicked by the Nightsister Asajj Ventress to become her mate and servant following her grueling tests of Selection, as part of her bid for revenge on her former Master, the Sith Lord Count Dooku. In accordance with their plot against Dooku, Mother Talzin and her Nightsister witches employed their dark magic to grant Opress fearsome abilities, placing him under their control.

Having survived his bisection in The Phantom Menace, striving to survive by any means, Maul ended up on a junk planet called Lotho Minor in the Outer Rim and turned into a cyborg with an arachnid-like lower half, and managed to survive with the help of the Anacondan named Morley. Over the decade, Maul's mind sank into a melancholy insanity before he was found by Opress. Opress's presence causes Maul to remember his downfall by Obi-Wan and resolves to have his revenge. Brought back to Dathomir, in the aftermath of the Nightsisters' slaughter by Dooku's forces, Maul undergoes a purging of his madness and is given a new pair of robotic legs crafted by Mother Talzin's magic.