Undead Fortitude. If damage reduces Sarlamir to 0 hit points, it must make a Constitution saving throw with a DC of 5 + the damage taken, unless the damage is bludgeoning or from a critical hit. On a success, the skeletal knight drops to 1 hit point instead.
Unusual Nature. Sarlamir doesn't require air, food, drink, or sleep.
Multiattack. Sarlamir makes three Enervating Blade or Throwing Axe attacks in any combination.
Enervating Blade. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit:15 (3d6 + 5) necrotic damage, and if the target is a creature, it can't regain hit points until the start of Sarlamir's next turn.
Throwing Axe. Melee or Ranged Weapon Attack: +8 to hit, reach 5 ft. or range 20/60 ft., one target. Hit:14 (2d8 + 5) slashing damage.