Your hero is Immune.
Mal'Ganis doesn't like being betrayed, so if you discard him, watch out.
Mal'Ganis was a Tier 5 minion in the Battlegrounds game mode.
It was replaced with Kathra'natir in August 2021.
Mal'Ganis was a strong backline minion for any Demon-based comps. He had a high stat baseline, the +2/+2 he provided benefited all your Demons, including tokens from Imp Gang Boss and Voidlord, and the damage immunity he provided meant you could continue to fuel Wrath Weaver even when you were near or at 1 Health.