How many RPs can ya be in?

[Albert Wesker]

How would armies work, like if I were to be in my universe a Kell (leader of an entire Clan/House of Fallen), how would that be handled if their in the hundred of thousands area, only theoretically assuming i GET that high.

This I honestly have no idea. Strictly speaking you're limited to five Secondaries per level of progression, so you would never approach anywhere near those numbers to begin with.

Also, is it possible to request for quests to make Artifacts or make a player-forged Artifact?

This is probably a no-dice. You can always put in the request, but Artefacts are supposed to be rare and in limited supply, due to their power and usefulness. We already have a fair number floating around as is. You're welcome to go crack someone's skull open and take their Artefacts if you like, though.