I wouldn't call this an AU but it kind of is and is not

Liveecin is an unknown item and the nickname of an entity. They create items called Truhon. Truhons are given to people the Liveecin perceives as a potential "Knight".

A Truhon can either empower or nerf someone. They are all different, and change their respective holder. Once given a Truhon, it can never be removed unless the Liveecin sees the current holder as obsolete or unworthy.

There is a whole facility working around Liveecin, checking on the knights, giving them their respective missions, and transporting the knights from universe to universe. The facility is called the Keleond. The Keleond communicates to the knights at the bare minimum, and is mainly only there for starting knights and universal travel. They depend on the knights to figure our what they're supposed to do and learn on the way, and to keep them from trying to back out of their responsibilities.

Truhons are rare and seem to choose their knights. They randomly appear in certain universes, and change its form to look like something valuable in that universe. Once its chosen knight interacts with it, it fuses with the knight and alters them physically and restrains or adds abilities.

Knights are always bound to three other knights, and come in groups of four. These four are supposed to stay together and never stray. However, they are given a lot of freedoms. Especially when beginning as knights. They are given a quest and are expected to do it eventually, and to learn on their own. Also to bond with their other knights. Some knights that are troublesome are put in groups of three with the fourth one added later on.

Knights are chosen for certain traits that are encouraged by their Truhon. You don't choose to be a knight.

Process:
Truhon appears in universe where their knight is, and look like a valuable item. Chosen Knight will find the Truhon and collect it. Most usually black out after that.
The Keleond usually transports them to another universe immediately with their fellow knights. After the knights meet and learn about each other, the Keleond gives their a brief about their mission and vanishes.
Knights figure out what they're supposed to do, and grow with their Truhons and fellow knights.
Next Universe, next mission.

Extra:
A Truhon can "replace" something when fusing to someone, making what "replaced" on the person white and more connected to Liveecin. E.g.: Decepticon Insignia on Cybertronian will be a white x symbol instead.
If there is nothing on the knight the Truhon can replace, it will alter something respective to the abilties and change it to white. E.g.: Weaponized arm will be altered and turned white.
Knights cannot return home or move universes without Liveecin or the Keleond helping.
Knights who start off as a trio usually go on a mission to find their last knight.
Every member in a Knight group are never from the same universe.