NPCs composing that spawngroup :

a_ghostly_student (100%)

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

frozenshadow_13, range=13 (378,511,23)

a_ghostly_student (50%)
a_ghostly_student (50%)

frozenshadow_18, range=161 (431,660,26)

frozenshadow_19, range=146 (376,659,26)

a_ghostly_scholar (50%)
a_ghostly_scholar (50%)

frozenshadow_21, range=106 (368,619,26)

frozenshadow_23, range=157 (481,619,26)

a_ghostly_scholar (100%)
a_ghostly_scholar (100%)

frozenshadow_24, range=173 (533,555,47)

#a_shrouded_bat (100%)

frozenshadow_25, range=113 (287,430,23)

a_ghostly_student (50%)
a_ghostly_student (50%)

frozenshadow_26, range=68 (336,451,23)

a_ghostly_student (50%)
a_ghostly_student (50%)

frozenshadow_27, range=45 (391,550,23)

a_ghostly_student (100%)

frozenshadow_28, range=91 (280,480,23)

a_ghostly_scholar (50%)
a_ghostly_scholar (50%)

frozenshadow_29, range=75 (310,461,23)

a_ghostly_scholar (100%)

frozenshadow_33, range=135 (499,525,23)

a_ghostly_student (50%)
a_ghostly_student (50%)

frozenshadow_34, range=86 (447,539,23)

a_ghostly_student (100%)

frozenshadow_35, range=160 (272,644,23)

Librarian_assistant (100%)

frozenshadow_36, range=188 (244,657,23)

Librarian (100%)

frozenshadow_38, range=190 (195,426,23)

a_ghostly_scholar (50%)
a_ghostly_scholar (50%)

frozenshadow_39, range=157 (503,437,23)

#a_ghostly_student (50%)
a_ghostly_student (50%)

frozenshadow_40, range=182 (538,456,23)

#a_ghostly_student (50%)
a_ghostly_student (50%)

frozenshadow_82, range=170 (263,376,-2)

a_shadowbone (50%)
a_shadowbone (50%)

frozenshadow_83, range=173 (414,347,-3)

a_shadowbone (50%)
a_shadowbone (50%)

frozenshadow_134, range=180 (431,345,-3)

a_shadowbone (50%)
a_shadowbone (50%)

frozenshadow_147, range=100 (265,501,23)

a_skeletal_hand (100%)

a_distant_voice_189751, range=196 (232,657,24)

a_distant_voice (100%)