Multiattack. The knight makes two attacks, using Flail or Javelin in any combination.
Flail. Melee Attack Roll: +5, reach 5 ft. Hit:7 (1d8 + 3) Bludgeoning damage—plus 4 (1d8) Necrotic damage if the knight is Bloodied—and the target has Disadvantage on its next attack roll before the start of the knight's next turn.
Javelin. Melee or Ranged Attack Roll: +5, reach 5 ft. or range 30/120 ft. Hit:6 (1d6 + 3) Piercing damage—plus 4 (1d8) Necrotic damage if the knight is Bloodied.
Knights of the Emerald Claw command squads of Humanoid or Undead soldiers. As they draw nearer to death, the chill of the grave suff uses their weapon attacks.