The void
The rest doesn't matter, your body is perishable, and, over the years, it may end up becoming useless. Once again, his idea of abandoning his physical strength and focusing on being a true combat mage turned out to be correct.
In this sense, Kayden also thought about how to achieve immortality. He had, in fact, already discovered a way to convert his body into mana, but this would end up causing problems in the future. Kayden would reach the same predilection that all false gods achieved.
Thoth was not wrong at any point in Kayden's life, not only was he the person behind many events in the universe. So, Kayden would take a leap of faith and chase the Lichs into the void. In the end, this was his best proposal.
"Finally," space, in all of Kayden's spiritual sense, began to shake. It was slowly closing in and shrinking. This was a clear sign that they would be expelled within a few minutes.