I haven't seen this book for over 5 years and, try as I might, I can't seem to find a single thing about it online.
Fantasy novel series.
I THINK that the cover usually had some type of arch in the background of the art work, and it would usually feature the main protagonist who was a knight (I think in some of the art, he'd be wearing loose cloth in a Greek robe-esque style).
He was travelling with an elf who wore stockings.
In one book, said elf gets trapped in a parallel dimension "jail"(???) and meets a dwarf, who I'm pretty sure gets killed later on.
The story kind of centres around this knight and him trying to beat this dark mage or something.
There was a point in one book where there was an enchanted forest surrounding a castle, and the forest and things inside it would attack whoever entered.
There was this female character. I can't remember whether she was a princess or not but her name started with a 'C;' it was a unique name, along the lines of 'Crysanthia' or something like that.
One other thing I think I remember was the knight and elf travelling and finding the knight's hometown, where he had built a home for his wife.
I read these books in about 2016/2017 and they were definitely a fair bit older than that, I say that due to the colour of the pages, condition of the books and the artwork used on the cover. I couldn't accurately estimate when it could have been published though.