NPCs composing that spawngroup :

a_bile_golem (50%)

a_sepulcher_skeleton (50%)

NPCs spawning around that spawngroup :
(Max range : 200)

charasis_114, range=25 (-42,444,22)

charasis_115, range=152 (7,565,23)

charasis_116, range=123 (7,531,22)

charasis_123, range=137 (3,549,21)

a_bile_golem (50%)
a_bile_golem (50%)

charasis_125, range=47 (-64,476,22)

a_bottomless_feaster (50%)
greater_war_boned_skeleton (50%)

charasis_127, range=149 (-170,532,14)

charasis_128, range=121 (-144,518,3)

a_bile_golem (100%)

charasis_129, range=116 (-116,532,14)

charasis_130, range=188 (-208,549,22)

an_undead_oblation (50%)
greater_war_boned_skeleton (50%)

charasis_133, range=94 (-156,429,22)

charasis_134, range=70 (-132,429,22)

charasis_136, range=194 (-72,234,23)

a_bottomless_feaster (100%)

charasis_142, range=194 (-72,234,22)

a_sepulcher_skeleton (100%)

charasis_143, range=81 (-144,423,22)

a_sepulcher_skeleton (100%)

charasis_146, range=122 (-6,320,22)

charasis_147, range=106 (12,353,22)

charasis_148, range=171 (9,273,21)

a_bile_golem (100%)

charasis_149, range=177 (-20,257,22)

charasis_205, range=195 (-95,621,23)

a_bottomless_devourer (100%)

charasis_208, range=135 (-127,548,4)

greater_war_boned_skeleton (100%)