Silverthorn
A slim rapier, gleaming but always a bit hard to see. Found on a dead halfling beneath Cleenseau. This was originally the possession of Rose Stonebridge, a halfling who lived in Cleenseau in the 1400s.
According to Marigold Stonebridge, Rose was one of the leaders of a resistance to hobgoblin occupation during the Dominion of Avatus. The matching sheath was given to Celyn by Marigold, and while not exactly magical, it appears to be exceptional at concealment, and with barely any effort the rapier can vanish into one’s cloak.
Mechanics
Requires Attunement
This rapier shimmers with sparkles along the blade and has an elaborate hilt. It seems to always gleam, and never gets dirty. By whispering a command word, the sword can become invisible until it is used in combat. When used to attack a creature while the wielder is unseen, a 19 or 20 counts as a critical hit.
Once per day, the Invisibility spell can be cast from the sword, targeting the wielder only. While sheathed in the matching sheath, perceiving the rapier requires a DC 25 Wisdom (Perception) check.