NPCs composing that spawngroup :

#A_Terror_Wraith (10%)

greater_war_boned_skeleton (90%)

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

citymist_77, range=87 (-175,-350,264)

citymist_78, range=61 (-114,-355,261)

citymist_79, range=79 (-146,-342,263)

gyrating_goo (50%)
gyrating_goo (50%)

citymist_98, range=93 (-117,-323,75)

citymist_101, range=43 (-120,-459,75)

citymist_139, range=36 (-136,-385,4)

a_shadow (16%)
greater_spurbone (16%)

citymist_140, range=67 (-134,-351,4)

plaguebone_skeleton (25%)

citymist_141, range=22 (-139,-422,5)

plaguebone_skeleton (20%)

citymist_152, range=69 (-100,-483,4)

citymist_153, range=69 (-97,-349,4)

a_haze_golem (33%)
a_lost_one (33%)

citymist_156, range=74 (-188,-395,4)

a_shadow (25%)
greater_spurbone (25%)

citymist_165, range=65 (-54,-400,10)

a_haze_golem (50%)
a_lost_one (50%)