Diehard

Your extraordinary constitution allows you to persevere through circumstances that would be lethal to lesser individuals. When you are reduced to 0 hit points but not killed outright, you become stabilized instead. Additionally:

• You are not knocked unconscious.

• Your speed is halved, your AC is reduced by two, and you can't use reactions.

• On your turn, you can use either an action or a bonus action, not both.

• Regardless of your abilities or magic items, you can't make more than one melee or ranged attack during your turn.

• If you attempt to cast a spell with a casting time of 1 action, roll a d20. On an 11 or higher, the spell doesn't take effect until your next turn, and you must use your action on that turn to complete the spell. If you can't, the spell is wasted.

If you take additional damage, you are unconscious and treated as having failed a death saving throw. If you receive healing, you regain your normal abilities. You can’t use this feature again until you finish a long rest.