I've been doing some MDH solo runs and I'm torn on the appeal of them, on one hand its fun to test what IDs are capable of but on the other a lot of it does come down to having specific sets of IDs for passives, EGO gifts for health/resources, picking the optimal floors/nodes and resetting a lot. Human fights are the worst because you're character defaults to the slowest speed enemy so you're either tanking 1-4 hits or resetting and if the character doesn't have dodge or get a decent amount of shield its purely luck. So far I've done R Faust, M Don, T Don, D Rodya and D Hong but they seem to be by far the easiest.