NPCs composing that spawngroup :

a_disabled_trap (100%)

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

frozenshadow_90, range=27 (606,-399,26)

a_shadow_beast_necromancer (100%)

frozenshadow_93, range=21 (582,-404,22)

a_shrouded_bat (50%)
a_shrouded_bat (50%)

frozenshadow_151, range=80 (577,-302,22)