Hellenistic rulers: conceivable epithets

[Maion Maroneios]

Ooops, before I forget: I wanted to give my armies epithets too. Iirc, an army is stratos, right?

Yep,that's right.

"the Western" (because they have fought at the Pillars of Herakles, pretty big thing for them)? Hesperios perhaps?

Well, Hesperia was the name the Hellenes gave to America. West is Dyse (ΔΥΣΗ), so maybe it could be Dytikos Stratos, or Western Army

"the First (Created)"? Protogonos?

Protogonos means 'of the first generation'. Now create is 'poio' (ΠΟΙΩ), so I believe it should be Stratos Protopoiethes (ΠΡΩΤΟΠΟΙΗΘΗΣ).

"the Royal / King's Own"? OK that must be Basilikos

Yes, Basilikos Stratos is fine.

"the Loyal / Reliable"?

Pistos Stratos

"the Armoured"? Kataphraktos?

Well, Kataphraktos means 'armored all over'. But it can be used. In that case, it would be, as you correctly stated, Stratos Kataphraktos.

Maion