Converting 5e CR to Classic HD
Challenge rating (CR) in Dungeons & Dragons, Fifth Edition determines basically everything you need to know about your monster: armor class, hit points, and average damage per round. This makes conversion between 5e and classic editions of D&D like B/X quite difficult, not only because of different conventions but also different expectations of how monsters and their math should function. Hits deal more damage than in classic D&D because characters add their ability bonus to the dice roll, and hit dice are kind of arbitrary and calculated retrospectively because what really matters is hit points by challenge rating (e.g.: a giant monster might have d12-sized hit dice whereas a medium monster might have d8-sized hit dice, but a CR 10 monster needs to have around 160 hit points either way). What do you if you're writing an adventure that you want to support both systems, but you don't want to work from scratch? My friend Nova found herself in this situation while...