NPCs composing that spawngroup :

a_bottomless_gnawer (33%)

a_sepulcher_skeleton (33%)

a_sepulcher_spectre (34%)

NPCs spawning around that spawngroup :
(Max range : 100)

charasis_a_pyre_golem23, range=35 (-90,692,22)

a_pyre_golem (100%)

charasis_Skeletal_Procurator71, range=30 (-89,675,21)

a_sepulcher_skeleton (50%)
Skeletal_Procurator (50%)

charasis_222836, range=35 (-90,657,22)

a_pyre_golem (100%)

charasis_222845, range=94 (-137,621,21)