NPCs composing that spawngroup :

a_bile_golem (33%)

a_bottomless_feaster (34%)

greater_plaguebone (33%)

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

charasis_87, range=181 (26,243,-194)

a_sepulcher_skeleton (100%)

charasis_98, range=165 (-284,120,5)

a_helot_spectre (100%)

charasis_103, range=125 (-273,182,4)

charasis_113, range=158 (-55,99,-194)

greater_plaguebone (100%)

charasis_118, range=161 (-12,147,22)

charasis_121, range=182 (12,147,22)

charasis_131, range=122 (-263,280,22)

charasis_132, range=98 (-221,296,23)

charasis_135, range=113 (-243,294,22)

charasis_136, range=83 (-72,234,23)

a_bottomless_feaster (100%)

charasis_137, range=70 (-221,246,23)

charasis_138, range=39 (-189,243,22)

charasis_139, range=34 (-188,222,22)

charasis_142, range=83 (-72,234,22)

a_sepulcher_skeleton (100%)

charasis_143, range=199 (-144,423,22)

a_sepulcher_skeleton (100%)

charasis_146, range=176 (-6,320,22)

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

a_bile_golem (100%)

charasis_149, range=138 (-20,257,22)

charasis_156, range=26 (-136,242,-162)

a_sepulcher_skeleton (50%)
greater_plaguebone (50%)

charasis_157, range=188 (25,165,-194)

a_pyre_golem (50%)
a_pyre_golem (50%)

charasis_158, range=141 (-25,165,-194)

a_pyre_golem (50%)
a_pyre_golem (50%)

charasis_165, range=101 (-226,152,4)

a_crypt_spectre_189514, range=113 (-237,147,5)