Gruumsh
Gruumsh is the patron deity of the Orc people. Gruumsh is considered to be an evil god by the broader world due to the different tenets promoted within Gruumsh worship, such as Orcish supremacy, raiding, and war.
Gruumsh worship amongst the Orcs has lessened overtime as Orcs try to assimilate in local communities and leave their old nomadic/raiding ways. Though some communities still worship Gruumsh in places such as the Orcholds or the Scablands. (and some orcs in burning empire?)