I love that in the doujins for Rebellion, Homura really isn't much of a devil at all but more of a tease. There are a couple of exceptions, but mostly she's really bad at the role and puts up a front.
That's basically Homura. She only called herself a devil because she brought God back to earth, not because she is a devilish person. Lots of Urobochi-style symbolism involved with that whole last few minutes of Rebellion.