I personally don't need a source, the evidence is enough for me in the game.
You have no concrete evidence. This is all speculation. You do realize this right? It's not truth nor false unless lore is provided. Just simple speculation. Kyne didn't teach Mortals the thu'um directly only granted them their ability. Nor is there any such Lore to state Kyne used Parthurnaax as her instrument. Parthurnaax took it upon himself to teach mortals the Voice.
Just wanna make sure you know you're not saying any real truth, just your personal head cannon as it were before you confuse other players.
I'm not the one that made that claim in the first place. Reread the thread. I couldn't care less about lore one way or another, Paarth dies in all my playthroughs because I don't trust him. Yes, I have speculated many, many times now after all the playthroughs and my speculations always lead to me agreeing with the Blades. Kill Paarth. He's a turncoat whether Kyne controlled him or not. Once a turncoat, always a turncoat. That's how I feel and that's why I enjoy killing him even more than Alduin, Miraak and Harkon. He's hid for thousands of years, but he can't hide from me.
Quote the OP if you feel like bickering about lore. I'm not interested. All I know is that his name means:
Ambition Overlord Cruelty and that Kyne
may have used him as an instrument. That's not deep lore, it's right on the wiki, but it's good enough for me. If I were so inclined, I would ask you for concrete evidence showing that he
wasn't controlled by Kyne. But really, don't bother because as I stated earlier, I couldn't care less.
In all honesty, in my opinion, bickering and debating Elder Scrolls lore is nothing but an exercise in futility. It's spotty and incomplete at best. You may as well rip half the pages from an American Civil War history book, read it and then debate it. Seriously a waste of time but it's your life, do what you want.