Caladborg and Knight of Thorn Achievement

[Cookieg.7024]

I'm having a problem. I've done the Caladborg greatsword some months ago and now I wanted to change its stats and I needed to talk to Ridhais but Ridhais isn't appearing in my home instance. Now, I've looked up in the forum and to see Ridhais I need the Knight of Thorn Achievement done (that gives 25 points plus a title) and I don't have it but I do have the Caladborg greatsword. I went to talk to the Pale Tree and she isn't blessing my greatsword, which doesn't allow to get that achievement.. How can this be solved?