There is evidence of this npc spawning in Apr2001:
Allakhazam's Magical Realm
Currently, the Militia Captain is 50/50 with Captain Bvellos. However, the depop mechanism, referred to above as 'unknown period of time', was malfunctioning. So, at best, you would only be able to momentarily see him.
Pending update:
-Corrected despawn behavior of Kael Militia Captain.
Is there any in-era evidence of Kael Militia Captain being a static spawn and not pathing?