Is something that is tainted by hell always corrupted by it or ruled by it?

On a cold dark night a small child is taken by the worst kind of humanity and imbued with unholy powers. The ability to change into any creature fictional or otherwise and to see someone's worst fears and if he wanted to make them come true. And ever since escaping he has run from those who wish to use him or harm him. Until he is finally captured and is sent to equestria by mistake. Can he convince those around him he isn't ruled by darkness. And when everything is on the line will he stay strong with his friends and see them all survive the dangers to come? And can he show a desperate queen that its always best to do the right thing even when the odds are stacked against you.