since no one has mentioned this using last arcs is ussally a bad Idea, cause you could be using that blood heat for better things like healing plus try to stay on the offensive while in heat modes, so you can heal and depending on char greif finish a combo with arcs when you are just about to run out, but personally I have only seen a last arc used in all the games I have played, I have seen however tons of ppl attempting to do final arcs and getting there faces pumpled in.
*a few ppl's have good last arcs if you accually connect kouma for instance also aoko cause you can BNB off her last arc.