Blue Blood Captain of the Cold Princess

Ethereal Sight. The ghost can see 60 feet into the Ethereal Plane when it is on the Material Plane.

Incorporeal Movement. The ghost can move through other creatures and objects as if they were Difficult Terrain. It takes 5 (1d10) Force damage if it ends its turn inside an object.

Multiattack. The ghost makes three attacks, using Withering Rapier or Necrotic Pistol in any combination.

Withering Rapier. Melee Attack Roll: +6, reach 5 ft. Hit: 13 (2d8 + 4) necrotic damage, and the ghost has Advantage on the next attack roll it makes before the end of this turn.

Necrotic Pistol. Ranged Attack Roll: +6, range 30/90 ft. Hit: 11 (2d10 + 4) necrotic damage, and the targets speed is slowed by 10 feet.

Etherealness. The ghost casts the Etherealness spell, requiring no spell components and using Charisma as the spellcasting ability. The ghost is visible on the Material Plane while on the Border Ethereal and vice versa, but it can’t affect or be affected by anything on the other plane.

Terror of the Seas. Wisdom Saving Throw: DC 13, one creature the ghost can see and isn’t an Undead. Failure: 10 (2d6 + 3) Psychic damage, and the target has the Frightened condition until the start of the ghost’s next turn. Success: Half damage.

Riposte. Trigger: The ghost is hit by a melee attack roll while holding a weapon. Response: The ghost adds 2 to its AC against that attack, possibly causing it to miss. On a miss, the ghost makes one Withering Rapier attack against the triggering creature if within range.