First Mate's Scabbard (Patreon)

Wondrous item, uncommon

This emerald green scabbard has been enchanted with the element of surprise. You can use a bonus action to speak the scabbard's command word to cause a sword that's sheathed in it to magically spring forward and strike at a target within 5 feet of either you or a friendly creature you can see within 30 feet of you. The sword makes a melee attack against the target (+5 bonus to hit, +2 bonus to the damage roll). If the target of the attack is a creature that hasn't seen this property of the scabbard before or is otherwise unaware of it, the attack roll is made with advantage. Hit or miss, the sword then flies to the open hand of a friendly creature of your choice within 5 feet of the target (which can include yourself) or lands on the ground at that creature's feet if its hands are full.

Once this property of the scabbard has been used, it can't be used again until the next dawn.

A new season, a new batch of recruits.

The old captain’s right arm was tucked into a sling for a few more weeks, but he didn't seem to care. He looked over the fresh faces, making mental and spoken notes, and rumbled disdainful words to his right hand officer about the rookies' lack of qualifications. The officer simply nodded and remained silent, watching carefully with their hand always behind their back.

It didn’t take long for one of the recruits to take a swing at the captain. There was always one. But, new to the armor, the clattering of metal on metal was more than enough warning for the captain. He ducked deftly to the side so the punch missed him clumsily, and shot a furtive glance at his second in command.

The silent officer uttered a single word and the blade on his hip shot forward, unsheathing itself from the verdant scabbard and slashing into the recruit's cheek. Without so much as a blink, the captain caught the flying blade in his left hand and continued to pace the line of new—considerably paler—soldiers.