It does seem very random, whether Aions who awaken to Horos out of the crystals from the shrines are regular humans or actual combatants. There's no rhyme or reason to the pattern so far, I'm afraid.

[It's a plain matter of observation.]

So you see this as a summoning, Saber?

[That's... extra interesting. The knight did say so as much during the dream, being more like a "ghost", but with a name like that and using this specific sort of wording? Hmm...]