NPCs composing that spawngroup :

an_enthralled_bulthar (50%)

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

sirens_48, range=48 (-640,-695,-152)

sirens_97, range=70 (-691,-695,-46)

sirens_98, range=30 (-668,-732,-58)

sirens_99, range=76 (-581,-695,-46)

sirens_100, range=31 (-610,-733,-58)

sirens_101, range=97 (-594,-657,-68)

sirens_102, range=42 (-639,-701,-58)

sirens_103, range=81 (-663,-665,-60)

sirens_104, range=82 (-614,-665,-60)

sirens_142, range=96 (-682,-656,-68)

sirens_143, range=87 (-727,-753,-68)

sirens_144, range=91 (-549,-754,-68)

sirens_145, range=5 (-638,-738,-25)

sirens_231229, range=61 (-649,-682,-60)

sirens_231274, range=97 (-681,-655,-68)

sirens_231275, range=98 (-593,-656,-68)

sirens_231277, range=79 (-644,-664,-60)

sirens_231286, range=82 (-614,-665,-60)