The Drygore Rapier is the 2nd best one handed melee weapon in the game, EVER so slightly beating out Crimson's Katana due to it providing defensive bonuses. However, some may find the Katana's prayer bonus to be more useful than the defensive bonuses the Rapier provides.
An unusual trait that the Drygore Rapier has is that it provides defensive bonuses, a trait shared by the Steel Tempest, and the Abyssal Tentacle.
Because the offensive stats are nearly identical to Crimsons Katana (higher stab bonus than slash bonus), this weapon could be used as an alternative to the Crimsons Katana when the stab bonus is needed.
Special shout out to Ned for providing all the information and pictures of this weapon.