We saw it in two, which isn't canon. But nonetheless, the demonic energy flows within himself...And I guarantee that eventually he can release a DT form without needing a Devil Arm. We are talking after dmc 2 time, and it being canon based... Even if you disagree that this will happen, don't you think it would be nifty though?
And I know Rebellion is a Devil Arm, it is Dante's official DT.
I know DMC 2 is by another team, what do you take me for?