Byzantine question

[Kraxis]

Heh... Revival... We are pretty good at that here in the Monastery.

I once read the manipular front-line guys first carried a javelin called something like hasta lancea (fairly literally "throwing spear", if my very poor Latin skillz are even close to the truth), as different from the larger close-combat hasta used by the heavier troops. The name apparently stuck around to cause some confusion later on when the only folks with something called hasta were the triarii...

Yup, that is basically what went down.
The Hastati were only guys to carry throwing spears (there is some debate wether they were truly javelins or some special heavy javelin, or even an early version of the pilum). And their primary combatrole was to cause shock. A hefty volley of javelins and a swordcharge to send the enemy into confusion and hopefully rout. But they were not meant to fight protracted battles, that was the job of the primary troops, the Principes. So while the primary troops had a spear to fight with it would make better sense to call them by their battlefield function. The first troops into combat would then be open to be called by their primary weapon, which would also give a short description of their battlefield function, just like the Principes. So it was logical at the time.
But just like we still call certain formations of armour, cavalry, advances in technology and tactics changed the troops but the names were easier to keep, and even at the time of Caesar (don't know about later periods) the three lines were still called Hastati Principes and Triarii despite being armed similarly.

So it is very much possible that what we have here is an outdated name for a 'modern' unit.
But of course I personally lean towards the author not really knowing what we wrote about and generally formed somethign that would fit historical texts. That wasn't too uncommon a few hundred years previously.