For Avenger OCs

A light blue-ish green portal opens up in front of you and (OC or character of your choice). You both have a mission to collect the shards of a powerful crystal that was split apart centuries ago to protect all of the multiverse. Once the shards were reunited the crystal would be used to stop an all powerful threat.

For Villains

You've been hearing about an ancient crystal that could bend the world to your will. The only thing you need to do is high jack the Avengers experiment to get the pieces.