| Mud mephit | 0.25 | Elemental | Small | 11 | 27 | fly, swim | neutral evil | | Monster Manual (SRD) | 8 | 12 | 12 | 9 | 11 | 7 |
| Mule | 0.12 | Beast | Medium | 10 | 11 | | unaligned | | Monster Manual (SRD) | 14 | 10 | 13 | 2 | 10 | 5 |
| Mummified warrior | 0.25 | Undead | Medium | 8 | 19 | | neutral | | Extra (AideDD) | 13 | 6 | 14 | 8 | 6 | 8 |
| Mummy | 3 | Undead | Medium | 11 | 58 | | lawful evil | | Monster Manual (SRD) | 16 | 8 | 15 | 6 | 10 | 12 |
| Mummy lord | 15 | Undead | Medium | 17 | 97 | | lawful evil | Legendary | Monster Manual (SRD) | 18 | 10 | 17 | 11 | 18 | 16 |
| Myconid adult | 0.5 | Plant | Medium | 12 | 22 | | lawful neutral | | Monster Manual | | | | | | |
| Myconid sovereign | 2 | Plant | Large | 13 | 60 | | lawful neutral | | Monster Manual | | | | | | |
| Myconid sprout | 0 | Plant | Small | 10 | 7 | | lawful neutral | | Monster Manual | | | | | | |
| Nabassu | 15 | Fiend (demon) | Medium | 18 | 190 | fly | chaotic evil | | Mordenkainen's Tome of Foes | | | | | | |
| Nagpa | 17 | Humanoid (nagpa) | Medium | 19 | 187 | | neutral evil | | Mordenkainen's Tome of Foes | | | | | | |
| Nalfeshnee | 13 | Fiend (demon) | Large | 18 | 184 | fly | chaotic evil | | Monster Manual (SRD) | 21 | 10 | 22 | 19 | 12 | 15 |
| Narzugon | 13 | Fiend (devil) | Medium | 20 | 112 | | lawful evil | | Mordenkainen's Tome of Foes | 20 | 10 | 17 | 16 | 14 | 19 |
| Necromancer | 9 | Humanoid (any race) | Medium | 12 | 66 | | any alignment | | Volo's Guide to Monsters | | | | | | |
| Necromite of myrkul | 0.5 | Humanoid (human) | Medium | 11 | 13 | | neutral evil | | Adventures (Descent into Avernus) | | | | | | |
| Needle blight | 0.25 | Plant | Medium | 12 | 11 | | neutral evil | | Monster Manual | | | | | | |
| Neogi | 3 | Aberration | Small | 15 | 33 | | lawful evil | | Volo's Guide to Monsters | | | | | | |
| Neogi hatchling | 0.12 | Aberration | Tiny | 11 | 7 | | lawful evil | | Volo's Guide to Monsters | | | | | | |
| Neogi master | 4 | Aberration | Medium | 15 | 71 | | lawful evil | | Volo's Guide to Monsters | | | | | | |
| Neothelid | 13 | Aberration | Gargantuan | 16 | 325 | | chaotic evil | | Volo's Guide to Monsters | | | | | | |
| Night blade | 0.25 | Humanoid (human) | Medium | 12 | 11 | | chaotic evil | | Adventures (Descent into Avernus) | | | | | | |
| Night hag | 5 | Fiend | Medium | 17 | 112 | | neutral evil | | Monster Manual (SRD) | 18 | 15 | 16 | 16 | 14 | 16 |
| Nightmare | 3 | Fiend | Large | 13 | 68 | fly | neutral evil | | Monster Manual (SRD) | 18 | 15 | 16 | 10 | 13 | 15 |
| Nightwalker | 20 | Undead | Huge | 14 | 297 | fly | chaotic evil | | Mordenkainen's Tome of Foes | | | | | | |
| Nilbog | 1 | Humanoid (goblinoid) | Small | 13 | 7 | | chaotic evil | | Volo's Guide to Monsters | 8 | 14 | 10 | 10 | 8 | 15 |
| Noble | 0.12 | Humanoid (any race) | Medium | 15 | 9 | | any alignment | | Monster Manual (SRD) | 11 | 12 | 11 | 12 | 14 | 16 |