So all of those creatures in the MM are monks.
— SnersonJim (@axdeath) September 25, 2019
A D&D monster might break the rules used by player characters. For example, a melee attack typically uses Strength, yet a monster might use Dexterity instead.
For more info on building monsters, see the "Creating a Monster" section in the Dungeon Master's Guide (p. 273). #DnD https://t.co/QQbYVtD1PX
— Jeremy Crawford (@JeremyECrawford) September 25, 2019