So that was what Sylas did.
The tree had 777 unique Time Runes and 777 unique Spatial Runes. Sylas wasn't sure why the numbers were so exact, or if this was just the exact limit that the sapling had right now. But he committed to learning them all.
Many of them overlapped, having the same—or abilities so similar that they almost weren't worth drawing a new Rune for—but Sylas didn't discriminate in the slightest. In fact, he sought out ones like that.
Runes that had the same function and yet crafted them through vastly different means were the best for establishing his foundation. The concepts from their similarities helped him to learn them faster while also deepening the understanding of the one that came before.