Homebrew

Actions

Multiattack. The sentinel makes three attacks, using Longsword or Longbow in any combination.   Longsword. Melee Attack Roll: +9, reach 5 ft. Hit: 9 ( 1d8+5 ) Slashing damage plus 22 ( 5d8 ) Force damage.   Longbow. Ranged Attack Roll: +7, range 150/600 ft. Hit: 12 ( 2d8+3 ) Piercing damage plus 22 ( 5d8 ) Force damage.

Bonus Actions

Manifest Echo. The sentinel summons an echo of their ancestor in an unoccupied space they can see within 15 feet of them. The echo disappears if it is destroyed, the sentinel is Incapacitated or summons another echo.   The echo has AC 18, 1 Hit Point and immunity to all conditions. The echo succeeds on all saving throws automatically. The sentinel can command the echo to move up to 30 feet in any direction on their turn. If the echo is more than 30 feet away from the sentinel at the end of their turn it is destroyed.   Echo Swap. The sentinel and the echo trade places with a teleport.   Second Wind (4/day). The sentinel regains 1d10+12 Hit Points.  

Reactions

Shadow Marty (2/day). Trigger: Attack against the sentinel or an ally. Effect: The attack lands on the echo instead of the sentinel or the ally. The echo is teleported to an unoccupied space within 5 feet of the targeted creature.   Indomitable (1/day). Trigger: Sentinel fails a saving throw. Effect: The sentinel rerolls the saving throw with +12 modifier and must use this new roll.