Credit to
Archade's Tower.
Detriment
Whenever a creature is struck by a critical hit, at the attacker’s option instead of the extra die of damage, the target may suffer a detrimental effect. Every non-permanent detriment can be automatically removed with the lesser restoration spell, or a short rest.
Impairment
If a character rolls a 20 on the detriment table above, or fails one or more death saves by 5 or more, they will discover an impairment upon regaining consciousness. Every non-permanent impairment can be removed with the lesser restoration spell, or a week of bed rest, unless the description says otherwise.
Injury
If a character rolls a 20 on the impairment table above, or takes more than its total hit points in a single blow, or rolls a 1 on a death save, they will gain an injury upon regaining consciousness.
