Do you? For the first battle it seems no matter who I fight, the base is 100 karma and the speed bonus goes 1.5, 1.4, 1.3 …, and the continued battles go 1x, 2x, 3x, 5x, 10x for me (that’s why I’ve been trying to choose weak opponents for the first match to finish quickly).
Right now the threshold to rank up is 4480 karma, which is rank 634. And I think this is the first time I’ve seen the class drop border go above 0 (or maybe I just haven’t been paying attention before)