Stalwart

Prerequisite(s): Constitution 13 or higher

You can go on fighting when others would collapse and give up. You have advantage on saving throws against being exhausted or stunned.

In addition, when you are stunned or exhausted, you can try to shake it off. You can use a bonus action to reduce your exhaustion level by 1. Alternately, at the end of your turn, you can make a new saving throw against any effect that has imposed the stunned condition on you, ending that condition on a success (the save DC is equal to that of the effect that stunned you, or DC 10, whichever is higher). In either case, once you use this ability, you must finish a short or long rest before you can use it again.