During his raid encounter in Aberrus, the Shadowed Crucible, Neltharion uses Surrender to Corruption to force players of a specified class to lose control of their character. This «class call» is an infamous mechanic returning from Blackwing Lair, where Nefarian used it to similar effect, causing chaos within the group if not carefully planned for. In both raids, players of the targeted class temporarily lose control, lashing out at enemies and allies alike.
Unfortunately, it seems like this ability may have been too difficult to balance across 13 different classes, as it has now been removed from the encounter journal, suggesting it may be gone entirely. Although an interesting and nostalgic gameplay mechanic, some groups had already theorized stacking classes to only deal with the easier calls, while avoiding bringing classes featuring more deadly ones. Starting from the timestamp, this video helps explain Neltharion's mechanic, as well as class stacking or avoiding issues it inadvertently created.
Shortly before its removal, however, we datatmined voice lines which would be spoken by Neltharion during each call. Although it looks like the mechanic may be gone, players can still enjoy hearing Neltharion condescendingly call out their class!
Death Knight NEW Neltharion takes hold of the death knight's powers of undeath, forcing them to death grip allies to their location every 6 sec. for 30 sec.Miserable Death Knight! Everything rots in your grip. Demon Hunter NEW Neltharion forces the demon hunter to erupt in a chaotic dance of blades every 6 sec. for 30 sec, causing them to inflict 83,222 Chaos damage to all creatures and players within 8 yards multiple times.
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