You gain the following benefits:
Ability Score Increase. Increase your Constitution score by 1, to a maximum of 30.
Last Stand. When you would be reduced to 0 Hit Points, you can drop to 1 Hit Point instead and regain a number of Hit Points equal to half your Hit Point Maximum. Once you use this benefit, you can’t use it again until you roll Initiative or finish a Long Rest.
Death Defiant. You succeed on every Death Saving Throw that isn't a roll of 1.