Yes, Durengal is a sword that was turned into a woman by Castir. It's a very NSFW origin. The series also seems to establish that Castir gained a crush on her.
Imagine how awkward that'd be; You're a sword that was turned into a human by a wizard, and now they're falling in love with you.
I would NOT want to be in that situation...
Trivia: Durengal's name is a portmanteau of 'gal' and 'Durendal', the name of a sword wielded by the fictional French paladin, Roland!
Link for more info: https://en.wikipedia.org/wiki/Durendal
I bet she'd be great friends with the Lemon Knight!
And before anyone asks, I didn't see an official tag for Zest Sprout's Mom, so I don't think she's an official character. Really cute, though!
However, there is something big that's going to happen soon. If you were clever enough to find a hidden message from a while ago, I applaud you for that. In case you didn't, let's just say that a certain story has finally been complete...