Hero
After obtaining Ezequiel's confirmation, Hyperion began to discuss the Sacred Trial with the other two bloodline Primarchs. Although the Titan Primarch would have preferred not to include them, he did not have a choice.
The Titan World's Sacred Trial was inside the world's origin, and it opened every one hundred thousand years. The last time it happened was roughly seven thousand years ago. Since they could not just wait for the trial to reopen on its own, they would have to do it manually, which would require a massive amount of resources.
Not even Hyperion could gather that much wealth on its own without harming his foundation, so he had to work with the Dragon Primarch and Sacred Beast Primarch. Of course, the Titan Primarch intended to milk as much wealth as possible from the duo.