NPCs composing that spawngroup :

spectral_guardian (80%)

tortured_librarian (20%)

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

kaesora_10, range=49 (93,-440,-101)

skeletal_minion (100%)

kaesora_11, range=22 (92,-394,-99)

guardian_of_Xalgoz (50%)
skeletal_minion (50%)

kaesora_26, range=25 (136,-409,-98)

failed_crypt_raider (10%)
spectral_guardian (90%)

kaesora_43, range=69 (167,-441,-101)

skeletal_warder (100%)

kaesora_65, range=58 (57,-395,-68)

spectral_guardian (100%)

kaesora_66, range=21 (134,-404,-99)

spectral_guardian (100%)

kaesora_74, range=31 (136,-371,-73)

an_iksar_spectre (50%)
a_tome_keeper (50%)

kaesora_87, range=92 (57,-323,-109)

kaesora_94, range=19 (116,-415,-99)

spectral_guardian (80%)
spectral_librarian (20%)