Brother Laz is a very hard boss in Diablo 2 LOD's MedianXL Mod, which changes absolutely everything. He's a secret boss with immunity against every single type of damage, meaning the players need to come up with a completely different strategy to beat him. If they however manage to slay him, he will drop a unique ring with insane stats that make the effort worthwhile. Although there isn't much that is done after slaying him, to be honest.