NPCs composing that spawngroup :

#The_Skeleton_Sepulcher (33%)

a_helot_spectre (33%)

a_sepulcher_skeleton (34%)

NPCs spawning around that spawngroup :
(Max range : 200)

charasis_5, range=110 (-513,-274,4)

hexbone_skeleton (100%)

charasis_36, range=190 (-373,-326,4)

charasis_37, range=172 (-387,-314,5)

a_bottomless_devourer (100%)

charasis_38, range=165 (-402,-314,4)

charasis_39, range=123 (-387,-250,4)

a_sepulcher_skeleton (50%)
a_sepulcher_skeleton (50%)

charasis_40, range=168 (-375,-301,4)

charasis_41, range=155 (-567,-296,4)

a_bottomless_devourer (50%)
a_helot_skeleton (50%)

charasis_42, range=86 (-553,-212,4)

charasis_43, range=109 (-579,-212,4)

charasis_44, range=181 (-652,-226,4)

an_undertaker_skeleton (50%)
a_sepulcher_skeleton (50%)

charasis_51, range=186 (-605,-31,4)

charasis_55, range=136 (-484,-32,3)

a_pulsating_bile (100%)

charasis_56, range=100 (-566,-117,4)

a_helot_skeleton (100%)

charasis_57, range=54 (-460,-117,4)

charasis_58, range=152 (-423,-27,8)

a_sepulcher_skeleton (100%)

charasis_93, range=116 (-367,-137,4)

charasis_94, range=115 (-389,-96,4)

charasis_97, range=186 (-408,4,14)

an_undertaker_skeleton (50%)
a_pulsating_bile (50%)

charasis_105, range=40 (-440,-156,5)

charasis_108, range=93 (-390,-138,4)

charasis_109, range=133 (-367,-96,5)

charasis_169, range=98 (-553,-103,5)

charasis_171, range=101 (-576,-139,3)

charasis_172, range=123 (-580,-97,4)

a_crypt_spectre_189513, range=40 (-439,-171,5)