Depending on equips and Tiers,you might find it better to move on sooner or hold back and do another lvl on easier mobs.

tyv outside lvl 1-4        (Cythris)
scythe outside lvl 2-6   (Cythris)
tyv inside lvl 4-7      (Cythris)
tyv inside lvl 2, lvl 7-9    (Cythris)
scythe inside lvl 7-10    (Cythris)
tearix lvl 9-13    (Cythris)
kraxis lvl 9-13    (Cythris)
kitalpha lvl 12-16    (Cythris)
Algedi lvl 13-17    (Cythris)
menkalinan lvl 16-20    (Cythris)
thuban lvl 17-21    (Cythris)
lesath lvl 19-23    (Cythris)
unukalhai lvl 19-23    (Cythris)
zoldar lvl 22-25    (Medusa)
koni lvl 22-27    (Sirrah)
arbendur lvl 23-27    (Medusa)
calarb lvl 24-28    (Sirrah)
kakarin lvl 27-32    (Medusa)
Myrmanss lvl 28-33    (Sirrah)
large asteroid lvl 29-33   (sirrah)
nidlex lvl 31-37    (Medusa)
alosont lvl 32-37    (Sirrah)
cron lvl 34-39    (Medusa)
bartroshon lvl 35-39    (Sirrah)
alioth lvl 37-42    (Medusa)
alioth inside lvl 48-52    (Medusa)
izar lvl 38-43     (Talitha)
izar inside lvl 45-53     (Talitha)
celbalrai lvl 50-54  (sorrow)    (Sirrah)
nogrisurnik lvl 51-55    (Sirrah)
honru lvl 53-57    (Medusa)
hydra outside lvl 55-60     (Talitha)
perceus outside lvl 55-60    (Sirrah)
cerebus outside lvl 55-60    (Medusa)
hydra inside lvl 58-63     (Talitha)
perceus inside lvl 58-63    (Sirrah)
cerebus inside lvl 58-63    (Medusa)
nashira lvl 68-70    (Sirrah)
crypt 70-73     (Talitha)

Protector mobs

Medusa lvl 24-36
Sirrah lvl 35-47
Talitha lvl 56-70

Bandit Bases

mintaka
altair
errai
markab
okda
rigel
zaniah
hadar

if anyone finds any incorrect data feel free to mention it in game and i'll edit it. hope this helps