You wanna see the most messed up class feature in all of 5e?
To determine your birthday, roll 1d12 for month and 1d30 for day.
When you reach a certain age, you must start making aging checks regularly at a certain interval of years. To pass an aging check, you must roll 4+ on 1d6. If you fail, your exhaustion limit (the amount of exhaustion at which you die) is reduced by one. If the limit reaches zero, you die. At a certain age, the difficulty of the aging check increases to 5+, and later to 6+.
If you succeed on an aging check, roll 1d4 on the Aging Effects table below.
1. Your life experience grants you XP equal to your age times your level times 5.
2. Randomly determine three different ability scores. Increase one of your choice by 1, and decrease another one of your choice by 1. The one you decrease has its maximum value reduced by 1.
3. You gain expertise with one skill or tool you have proficiency with.
4. You have entered the golden years. Until you fail an aging check, you gain inspiration on each of your birthdays. This effect can stack, granting you several instances of inspiration.
Your starting age, the age at which you must start making aging checks, the ages at which the difficulty of the check increases, and the interval in years between the checks, are all determined by your species.
| Species | Starting age | Interval | Aging 4+ | Aging 5+ | Aging 6+ |
|---|---|---|---|---|---|
| Aarakocra | 2+1d3 | 2 | 6 | 16 | 26 |
| Aasimar | 15+3d8 | 8 | 64 | 104 | 144 |
| Bugbear | 13+3d6 | 4 | 32 | 52 | 72 |
| Cat | 1d4 | 1 | 5 | 10 | 15 |
| Centaur | 15+3d6 | 4 | 36 | 56 | 76 |
| Changeling | 13+2d6 | 4 | 36 | 56 | 76 |
| Dragonborn | 13+2d6 | 4 | 36 | 56 | 76 |
| Duergar | 15+3d8 | 24 | 120 | 240 | 360 |
| Dwarf | 15+3d8 | 24 | 120 | 240 | 360 |
| Eladrin* | 15+3d8 | 40 | 40 | - | - |
| Elf* | 15+3d8 | 40 | 40 | - | - |
| Fairy | 15+3d6 | 4 | 60 | 80 | 100 |
| Firbolg | 15+3d8 | 28 | 140 | 280 | 420 |
| Genasi | 15+3d6 | 4 | 72 | 92 | 112 |
| Githyanki** | 15+3d6 | 4 | 36 | 56 | 76 |
| Githzerai | 15+3d8 | 8 | 56 | 96 | 136 |
| Gnome | 15+3d8 | 28 | 140 | 280 | 420 |
| Goblin | 7+1d6 | 4 | 14 | 34 | 54 |
| Goliath | 15+3d6 | 4 | 36 | 56 | 76 |
| Half-elf*** | 15+3d8 | 4 | 40 | 60 | 80 |
| Halfling | 15+3d8 | 8 | 40 | 80 | 120 |
| Half-orc | 12+2d6 | 4 | 28 | 48 | 68 |
| Harengon | 15+3d6 | 4 | 36 | 56 | 76 |
| Hobgoblin | 15+3d6 | 4 | 36 | 56 | 76 |
| Human | 15+3d6 | 4 | 36 | 56 | 76 |
| Kenku | 11+1d6 | 4 | 20 | 40 | 60 |
| Kobold | 5+1d6 | 8 | 24 | 64 | 104 |
| Lizardfolk | 13+1d6 | 4 | 20 | 40 | 60 |
| Loxodon | 15+3d8 | 28 | 140 | 280 | 420 |
| Minotaur | 15+3d8 | 8 | 100 | 140 | 180 |
| Orc | 10+2d6 | 2 | 26 | 36 | 46 |
| Satyr | 15+3d6 | 4 | 36 | 56 | 76 |
| Sea elf* | 15+3d8 | 40 | 40 | - | - |
| Shadar-kai | 15+3d8 | 56 | 180 | 460 | 740 |
| Shifter | 8+2d6 | 4 | 24 | 44 | 64 |
| Simic hybrid**** | ? | ? | ? | ? | ? |
| Tabaxi | 15+3d6 | 4 | 36 | 56 | 76 |
| Tiefling | 15+3d6 | 4 | 40 | 60 | 80 |
| Tortle | 13+2d6 | 2 | 32 | 42 | 52 |
| Triton | 15+3d8 | 8 | 100 | 140 | 180 |
| Vedalken | 36+4d6 | 28 | 140 | 280 | 420 |
| Yuan-ti | 15+3d6 | 4 | 36 | 56 | 76 |
*Eladrin, elves, and sea elves are immortal. When they fail an aging check, their exhaustion limit is not reduced. Instead, they incur a cumulative -10% penalty to all XP gained. This can eventually prevent them from gaining XP entirely. Successful aging checks do not grant a roll on the Aging Effects table.
**For a githyanki, time spent in the Astral Plane does not count towards their aging. They still use their full age and actual birthdays for effects from the Aging Effects table. A starting githyanki character is assumed to have spent half their life so far in the Astral Plane.
***When a half-elf reaches age 40, they must choose whether to accept or refuse immortality. If they accept, they age as an elf. If they refuse, they age normally using the given values.
****Simic hybrids use the values of their origin species. The ages at which they must start making aging checks, and at which the aging check increases in difficulty, are reduced by a number of years equal to the origin species' interval. This does not apply if their origin species is eladrin, elf, or sea elf.