NPCs composing that spawngroup :

an_army_behemoth (20%)

a_berserk_fiend (20%)

greater_plaguebone (20%)

greater_war_boned_skeleton (20%)

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

citymist_52, range=52 (194,-14,-9)

citymist_57, range=82 (219,-88,1)

citymist_66, range=36 (143,-6,274)

a_deranged_madman (50%)
greater_plaguebone (50%)

citymist_119, range=23 (140,-21,-9)

a_shadow (20%)
greater_spurbone (20%)

citymist_172, range=54 (102,-67,2)