NPCs composing that spawngroup :

an_apparition (25%)

an_apparition (25%)

an_army_behemoth (5%)

a_fog_golem (45%)

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

citymist_102, range=65 (-116,-566,75)

citymist_103, range=22 (-138,-636,76)

citymist_142, range=99 (-231,-557,3)

Captain_of_the_Guard (10%)
greater_spurbone (90%)

citymist_143, range=1 (-154,-620,5)

an_apparition (50%)
greater_spurbone (50%)

citymist_144, range=67 (-141,-553,3)

citymist_145, range=86 (-236,-593,3)

Captain_of_the_Guard (10%)
greater_spurbone (90%)

citymist_146, range=29 (-138,-594,3)

an_apparition (100%)

citymist_149, range=77 (-230,-623,23)

citymist_150, range=81 (-234,-626,5)

a_shadow (16%)
plaguebone_skeleton (16%)

citymist_162, range=63 (-100,-584,22)

citymist_163, range=59 (-100,-645,23)

citymist_223157_takp_import_v0, range=44 (-130,-657,75)

gyrating_goo (100%)

citymist_222970_takp_import_v0, range=34 (-131,-645,76)

citymist_222977_takp_import_v0, range=41 (-117,-640,77)

citymist_222963_takp_import_v0, range=91 (-152,-528,3)

citymist_222961_takp_import_v0, range=80 (-233,-625,3)

citymist_222964_takp_import_v0, range=76 (-229,-622,21)

citymist_222958_takp_import_v0, range=78 (-95,-566,23)

citymist_222955_takp_import_v0, range=59 (-99,-644,23)

citymist_Captain_of_the_Guard000_10021963, range=11 (-154,-631,21)

Captain_of_the_Guard (100%)