NPCs composing that spawngroup :

a_sepulcher_skeleton (100%)

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

charasis_124, range=82 (-62,429,21)

a_bile_golem (50%)
a_sepulcher_skeleton (50%)

charasis_125, range=96 (-64,476,22)

a_bottomless_feaster (50%)
greater_war_boned_skeleton (50%)

charasis_128, range=95 (-144,518,3)

a_bile_golem (100%)

charasis_133, range=13 (-156,429,22)

charasis_134, range=13 (-132,429,22)