You have the indomitable will and endurance of a veteran fighter.  You have seen countless combats and know that often times, the difference between winning and losing comes down to sheer determination.  You are focused, and single-minded.  This relentlessly dogged attitude gives you an advantage in life and death circumstances:

• If you are of the Fighter class, your Second Wind ability, when used, allows you to regain hit points equal to 10 + your fighter level during a bonus action, rather than 1d10.
• If you are not of the Fighter class, you gain the Second Wind ability, allowing you to regain 1d10 hit points during a bonus action.  Available once per short or long rest.
• You have advantage on death saving throws.
• Your Constitution score is increased by 1.