The thrum of the Weave, or so Zariel had called it, had been a hint Altair had decided long ago. A phrase that he had overlooked amidst his battle for supremacy against the Vale King. Peering through his eyes, listening to words spoken by his persona, had given him a lot of time to think. To recount past actions and learn from them.
The Weave he had learned was reality itself, woven into creation by the Almighty, containing everything to be and everything that was. And Zariel could not just see it but control it, nearly granting him nigh omnipotence.
Altair wasn't as arrogant as to believe he would obtain such a power. No. He was quite content with wielding omniscience. The only issue was how to wield it to his advantage. The idea had been rattling in his mind for quite some time, but he found it difficult to imagine creating a mental picture of what he was supposed to do.