The The Martyr Class for Dungeons & Dragons (D&D) Fifth Edition (5e)

Base Class: Fighter

You fight and die for your cause, holding nothing back. You are always prepared to sacrifice your very being to ensure victory. The Martyr spurs others onto greater feats of strength and valor. Your commitment to duty and cause are unmatched, and your willingness to die for your friends is only somewhat disturbing to those around you.

Sacrifice

3rd level: you are able to cast the Life Transference spell at 3rd level without needing spell components, once per short or long rest.

Final Stand

7th level: your great vigor empowers you when in mortal danger. Whilst your remaining number of hit points is equal to, or lower than, your double your fighter level you are resistant to all forms of damage.

Death Cry

10th level: you will not go silently, but with a roar. Once per short or long rest, when you are reduced to 0 hit points or lower you release a resounding cry. You can use one of the following Death Cries;

Battle Scream. Your cry echoes around the battle field, granting each allied creature within 60 ft advantage on all attack rolls and ability checks on their next turn.

Frenzied Shout. Your voice hastens your allies. Each allied creature within 60ft that can hear you gains one additional attack action on their next turn. This can only grant one additional attack to each creature.

Imposing Roar. Your shout strikes fear into your foes. Every enemy creature within 60 ft that can hear you and has an Intelligence score of 6 or higher must make a Wisdom saving throw against a save DC equal to 8 plus your proficiency bonus plus your Constitution modifier. On a failed save, creatures become frightened of you for 1 minute during which they are unable to move closer to your body and their attack rolls and ability skill checks are at disadvantage.

Rallying Cry. You release a scream that empowers your allies. Every allied creature within 60 ft that can hear you gains temporary hit points equal to your Constitution modifier for 1 minute.

Warrior's Howl. Your cry fills you with determination. You instantly regain hit points equal to your fighter level.

No Price too Great

15th level: You gain the ability to use your life force for others in a variety of new ways;

Blood Soaked Smite. As a bonus action, after you succeed on a melee attack roll you can sacrifice any number of your remaining hit points, unless it would bring you below 1 hit point. For every two hit points you sacrifice your attack deals 1 additional weapon damage. You can use this ability once per short or long rest.

Price of Life. As an Action, you can sacrifice all your remaining hit points to bring a creature that has been dead no longer than 24 hours back to life. When you do this you must immediately roll a death saving throw, if you fail you die and if you succeed you become unconscious and unstable.

Touch of Grace. As an Action, you can expend one of your remaining hit die to instantly heal an unconscious creature within 5ft by 1 hit point.

Martyrdom

18th level: if you are killed in battle your spirit emboldens those who stood with you. Every ally within 1 mile gains the following benefits for one day;