By the way, Dark element is connected with gravity or space or something in universe. It basically the black stuff in the background of space, lol. It is also a very hard to use element, and a double edged sword sometimes. For example, he can't shoot bolts of darkness since he doesn't have the mind powers for it, so instead he uses it for it's basic function: enhancing inertia to be more powerful than it actually is. What this means is that it enhances anything with momentum, but if it ain't moving, it will not do much. The bad side effect of Darkness is that since it enhances inertia only and not the actual molecules of the object it's "enhacing", that object will break if the force is too much for it. So basically he could shatter his arm if he punches with enough darkness in it, so he has to use his sword, which can take up to x6 it's maximum momentum. Since his strength isn't enhanced, he can't really use it to overpower a strong opponent long term. Literally, just burst attacks is what Darkness is good at. (And if his mind power is high, he could have been able to fire bolts of darkness, which would just destroy the psi bolt it rides on).