Board Thread:Off Topic/@comment-26064215-20150127201253/@comment-25396609-20150416150642

My theory is that they feed on negativity, the one he keeps locked up gets all the energy it needs just from being around him, and the fear of the people he feeds to it help to keep it alive when he's not around.

although considering he has control over a moderately sized dust mine on Menagerie i could just say he has a section of the mines closed off for it to live in, probably adjacent  to his own base of operations, or that it has learned that if it doesn't attack him he will make sure it has plenty of prey. I'm still working on th specifics, and that arc won't come until MUCH later so I have plenty of time to figure it out.