Hela was Odin's daughter. In the past, Odin was a more war - like figure, and Hela was his enforcer. She helped him conquer many lands. However, as Odin's views changed, he saw Hela as a threat to the peace he now desired. So, he banished her. Odin didn't want her to continue her reign of terror. This is the basic hela and odin back story which led to a lot of conflict when Hela finally broke free from her prison in the later storylines.
The key elements include Hela's origin as Odin's firstborn. Her role as a powerful weapon in Odin's early conquests. And then Odin's transformation which made him see Hela as a danger. He feared that she would continue her violent ways and disrupt the peace he was trying to build. So, he took the step of locking her away, which is a major part of their back story.
Obviously, Ash is the most important character as the story revolves around his death and return. Pikachu is also crucial as his closest pokemon companion. His friends like Misty, Brock, and Serena would play significant roles as they would be affected by his death and overjoyed at his return.
In such a fanfiction, a common plot point could be the shock and grief among Ash's friends when he dies. Maybe Pikachu refuses to leave his side at first. When he returns, he might have some new powers or a different perspective on his pokemon journey.
Another possibility is Heimdall. As the all - seeing guardian of the Bifrost, he would be aware of Odin's situation from the start. He could be the one trying to piece together what happened to Odin and prevent any disasters that might occur as a result of Odin's wipe. His unique abilities and loyalty to Asgard would make him a strong candidate for the main character.
Hela is a major villain in the Marvel Comics universe. She's the daughter of Loki and has the ability to control the undead. Her powers are quite formidable and she poses a significant threat to the heroes.
Hela is one of the mightiest villains in the comics. Her strength lies in her magic, which allows her to do things like raise armies of the dead and manipulate reality to an extent. Also, she has superhuman physical attributes that make her a formidable opponent.
Hela is one of the most formidable characters in comics. Her powers include the ability to raise the dead, manipulate dark magic, and possess superhuman strength and durability. Her domain over death gives her a significant edge in battles.