The Avengers: Earth's Mightiest Heroes Wiki
"The Odinsleep nears. Once a year, I must slumber to regain my strength. So that Asgard may live."

Odinsleep is a hibernating sleep of Odin to replensh his OdinForce. All of Asgard's armies and warriors defend him at all costs when dark forces attack Asgard until Odin wakes up from his deep slumber.

Thor was the one primarily in charge of guarding the AllFather until he grew tired of the endless cycle of battle and went to Earth for a real fight. Loki used to defend his stepfather in his younger years until discovering the truth and proceeding along his own dark path.

The Odinsleep has granted Loki an advantage over his enemies. He distracted Thor by releasing the frost giants and defeated his former Asgardian friends with his evil forces.

After the OdinForce returned to Odin, he woke up from the Odinsleep and banished his stepson to the bottom of Midgard.

The Odinsleep will be endless for Odin until he dies or is succeeded by Thor.