You gain a +1 bonus to attack and damage while wielding this magical weapon.
This rapier first appears to be a plain, solid metal bar measuring approximately 6 inches long. The bar has a hidden button which can be found with a DC 20 Intelligence (Investigation) check.
Pressing the button activates springs and gears hidden inside the bar that unsheath the weapon, causing a retractable blade to spring forth from the top, a small pommel to emerge from the bottom, and curved metal to extend from the sides creating a simple ringed hilt around the wielder's hand.
Pressing the button again sheaths the weapon, returning it to its original appearance as a plain, solid metal bar.
Proficiency with a Rapier allows you to add your proficiency bonus to the attack roll for any attack you make with it.
This weapon has the following mastery property. To use this property, you must have a feature that lets you use it.
Vex. If you hit a creature with this weapon and deal damage to the creature, you have Advantage on your next attack roll against that creature before the end of your next turn.
Notes: Bonus: Magic, Damage, Utility, Combat, Deception, Finesse, Vex
This is very elegant and very cool. My only suggestion would be that it could be an additional DC 25 check to determine which end the rapier's blade springs from, first time you use it. Could be fun, or horrible...
Remember kids, always hold mysterious button-wands with both ends pointed away from friends and towards people you dislike.
Ooo that's an idea, obviously this could be easily houseruled at the time, but it would be fun to have a special one-use attack where the action you use to activate the rapier can also be used to make a single thrust that deals bonus damage. Juuust an idea though. Perhaps the attack would be made with advantage due to surprise but have a chance of going horribly awry due to the spring-loaded force of the thrust. If you miss even with the advantage you get disarmed, perhaps? Hmm this is probably very annoying. This item is great, don't mind me. :P Just ideas all over the place.
I realize this is almost six months after you posted the comment, but I just saw it. First, thanks for the compliments! I'm glad you like the item and it inspired you to come up with some ways of adding on to it. The extra check to see which end it pops out could be quite funny.
Your idea about a surprise attack reminds me of the Russian Spetsnaz knife that can fire the blade from the handle. Perhaps I'll brew up a weapon that does something similar. :)
Thanks again for the comment!
Were I to construct one in-character, I'd deliberately make it obtuse which end actually opened up in case of thieves, albeit with clear markings for myself (asymmetric pattern). Coinflip time! :P
As to the surprise attack, I realise it's probably best to just houserule that as one way to get Surprise in a social situation, or similar. But that does sound like a cool concept on its own as you say... I assume it's an Interaction to push the button? That could get interesting in duels on its own.
I really enjoy mechanical weapons like this and have a few more I made for the campaign I was DMing. I had made the player another rapier that matched (they were a dual-wielding rogue) that could attach together to turn them into a shortbow.
As for rarity, uncommon is totally reasonable, especially in Eberron. A +1 sword is uncommon and I can see the argument that the concealment ability is a ribbon that doesn't necessitate bumping up a level in rarity.
This is really fun but I would like to mention that Rapiers don't have pommels.
Thanks! I’ve seen quite a few sources with pommels on rapiers, but if you have more info about them please feel free ti message me. Glad you like the item!