Monk/Master do have some special rules. They gain power when barehanded to compensate for the lack of a weapon, and this power grows much faster than the power ‘growth’ of equipping new weapons. In DoS, it gets even better as they actually get double hits when barehanded, meaning you should be using a barehanded Monk right from the start. While your Hasted Knight is dishing out 16 hits per attack, your unbuffed Monk is also dishing out 16 hits per attack. With Haste and one use of the Giant’s Gloves, a Monk can make 36 hits per attack. 36! It’s insane. And with constant use of the Giant’s Gloves (Temper and Sabre are stackable spells), you can eventually raise this much MUCH higher.
Monk/Master also gains extra defense when ‘naked’ based on Stamina. In the early game, it’s actually better to wear no armor as it adds no defense but it still lowers evade. A few armors will still boost defense late-game (Diamond Armlet, Power Vest, Crystal Ring, Tiger Mask), and some are just plain useful despite lowering defense (Ribbon, Twist Headband, Protect Ring), but if you raise Stamina to 99, even the best armors will likely lower defense. Though the added effects still make them useful to equip (I <3 Ribbons).