User blog comment:Jett Cyber/Tournament of Legends: Battle Blog 1/@comment-9062114-20131104164431/@comment-13446185-20131106120051

Because Alduin kind of damned him.

"I take away your ability to jump and jump and jump and doom you to [the void] where you will not be able to leave except for auspicious days long between one and another and even so only through hard, hard work."

"And he knew that the last world had been eaten entirely, except for its stolen portions, and that when the new kalpa began to form The Greedy Man (who never stayed trapped for long) would begin sticking these stolen portions back on in the craziest of places, and that he himself could never jump again until all was put back right."

Dagon just wants to do is be the Leaper King again but the task required to reach this objective is very very hard.