NPCs composing that spawngroup :

a_dread_bone (50%)

a_shadowknight (50%)

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

befallen_49, range=58 (-592,-97,-69)

befallen_48, range=76 (-620,-90,-67)

befallen_47, range=47 (-512,-79,-66)

befallen_46, range=82 (-480,-94,-67)

befallen_77, range=77 (-627,-33,-67)

befallen_93, range=98 (-456,-31,-38)

a_greater_skeleton (50%)
a_sturdy_skeleton (50%)

befallen_98, range=34 (-586,-60,-39)

befallen_100, range=81 (-488,-105,-38)

a_large_plague_rat (50%)
a_necro_neophyte (50%)

befallen_123, range=82 (-571,26,-39)

befallen_124, range=72 (-556,18,-38)