Legend of the 52 Warriors
#5) Rhontodon

Heh, his name sounds like it could be a Pokémon.

From the notes of Ezra Thrine:
Rhontodon spent the majority of his early life as Alpha Male of a large herd of wild elephants. He was, quite possibly, the largest and mightiest elephant to ever walk the Earth.
Rhontodon would often leave his herd, going out to sew his wild oats among other herds. He returned from one such trip to find his entire herd murdered and the males stripped of thier tusks. In his confusion, pain, and rage, Rhontodon's guard was down- enabling the ivory poachers who killed herd to capture him.
For several years, Rhontodon endured a living Hell. A magic talisman that promoted amazing bodily regeneration was placed around his neck. Every several days, the poachers put Rhontodon though terrible agony; extracting his proud tusks and submitting him to awful procedures that would encourage them to grow back bulkier and bulkier.
All day and every day, he would strain against his restraints- unable to break them, but growing stronger and stronger. Finally one day he was able to break loose and escape his captors. Once free, with his titanic strength Rhontodon punched through the very barrier of space and time, ending up just outside of the Eternal Library.
The struggle to gain Rhontodon's trust was surprisingly brief considering what he'd been through. He now lives happily here in the library, ready to defend should the need arise.