D&D is a game of action heroics. Often a power fantasy of casting spells and cutting down monsters and taking their stuff. While it’s made to be adventure fantasy, not all fantasy is about total power over your enemies – some of the best fantasy is when characters put themselves at risk by throwing themselves in front of oncoming danger for the greater good. Heroes also win from sacrifice.
The Dangerous
I Grab them: You use your reaction to grab hold of a suddenly falling companion that is within reach. Roll a DC20 Dexterity saving throw, on a success you grab a hold of them before they plummet. Next check your encumbrance vs their weight. If within your carrying capacity make a DC 15 strength or Athletics check to pull them 5 feet to safety (increase or decrease the DC by 5 for each size category of difference), if you fail and you are stuck holding onto them and your speed is reduced to 0. You can try again as an action at the start of your next turn. If you fail by 5 or more you lose footing and drop them as you fall suffering the same fate you tried to prevent. If the person you tried to grab is beyond your strength to lift you automatically fail and they slip from your grasp.
The Self Sacrifice
These are options that have a high to an almost certain chance of killing your character. It is considered a suicidal act so cannot be ordered to be performed by a Dominated or Charmed creature. These are the sudden leap to protect a companion by throwing yourself in the way of the attack and making your last stand to hold the line against certain doom it gives your party a chance to escape. Fly you fools!
Noooo!: You use your reaction to leap in front of an oncoming targeted attack of a companion within 10 feet, making yourself completely vulnerable to the attack to stop it from reaching them. You can do this when they are declared to be hit but before damage is rolled. Move immediately up to 10 feet to be beside the creature you are defending. Roll a DC 15 Dexterity saving throw. On a success the attack hits you instead, it is an automatic critical and you are vulnerable to the damage. You fall prone in the attack area and are stunned until the end of your next turn. The attacker loses any further attacks for this turn and immediately ends their turn. On a failure, you fall prone with no further effect.
Hold the Line: As a readied action you put yourself between the enemy and your party attempting to sacrifice yourself so your party has a few more seconds to escape or to complete some action. Your level must be at least half your opponent’s CR to attempt this and be able to block their path. You reduce the opponent’s movement to 0 as soon as you are within reach, they receive no more actions or legendary actions for the rest of the turn and cannot act until after the end of your next turn. Roll an opposed roll. Roll a d20 and add your level and your opponent adds their CR. If the opponent loses you drop to 1hp and can hold them for another turn causing the same effects then they suffer 10% of their current HP in damage if you could normally harm them. If you fail you are reduced to 0 and die immediately. Your body is likely heavily mutilated or destroyed requiring a True Resurrection for any chance of recovery.