Get Up!

You have to get up. It can't end here. Whether it's because there's someone who needs you or because you are simply too angry to die, GET UP.
This grants you the following abilities:

• Add 1 to your Constitution score to a max of 20.
• When you drop to 0 health points, you can fill a failed saving throw circle to get back up at the start of your next turn with 1/3 of your max health rounded up. If you go down again, you can fill the rest of your failed saves to get back up again with another 1/3 of your max health rounded up. You die for good if you are brought to 0 HP again in this state.
• If you get up twice, your failed saves stay stay filled until you've long rested twice.
• Once you use this ability, you cannot use it again until you have completed at least one long rest. (You cannot get up a second time unless you have 2 failed save slots free).
• You can add your Constitution modifier to any death-saving throws you make.