Far Out There: Avatar's Profile

To put it simply, Avatar is the embodiment of mad science at its most silly and impractical. One day, a secret cabal of mad scientists got together and decided that the universe was doomed. Rather than attempt to actually SAVE the universe, they instead devoted their energies to creating a storage receptacle capable of preserving the recorded knowledge of humanity after all or most of existence ceased to be. Since simple preserving raw data would be of little use if there was no one around to read it, that data storage device was incorporated into a human brain that would be able to appreciate the knowledge it stored. The end result: a virtually indestructible, astonishingly intelligent little girl named Avatar.
Avatar's whole purpose in life is to wander the universe learning everything she can, so that she'll be able to remember it all when everything goes kaput. You'd never know Avatar has such a morbid life's mission from looking at her though. She's a relentlessly cheerful, precocious little scamp who seems more interested in amusing herself than ingesting the entirety of human wisdom. Not that she can't rattle off some wildly obscure bit of historical knowledge when she feels like it, of course.

It's already been mentioned that Avatar is virtually indestructible: her body was built to withstand the demise f the known universe, of course. The funny thing is, indestructibility is actually wildly inconvenient for a girl to deal with. For example: since her body is designed to function without needing food or air, eating makes her sick and being in an atmosphere too long makes her queasy. Hence, she needs to take refreshing strolls through the cold vacuum of space from time to time. Oh, and since her cells can't decay, Avatar is physically incapable of growing. How she remains cheerful in the face of THAT is anyone's guess.