Ryze: A World Rune's Avatar?

In Ryze's new cinematic he finds a red world rune and stores it in an unknown place along with three others a purple a yellow and a green yet there is clearly place for a fifth one. In his current splash art he is holding the purple rune and according to the new Ryze comic, The Burning Lands, Brand got his power from a world rune. The world runes are supposed to be items of unthinkable power but in the comic Ryze seems to be able to hold his own against him and even trap him in a rune cage. He would not be able to do this unless he power was equal or grater to the of brand. Ryze also deals extensively in runes and nothing but another world rune could match the power of a world rune's "avatar." If so it would make sense that Ryze got his power through the Purple rune. Tell me what u guys think!