Dang, I have a muse who would actually fit really well and even be kinda hilarious for it since he's like the opposite of Colette and would end up being part demon. He even looks a bit like Colette with his blond hair and blue eyes. The character is Hugo Fact from Ys Origin, here's a pic of him.

But am hesitant to app him because he's got a bit too much in common with Tamara personality wise, he's just a bit more snobby and his snark is more saying the blunt and honest truth in a humorous way and with a straight face (see this for an example). So that would end up being three characters for me with a tendency to be a troll. But I admit, I was a bit sad to have dropped him when I did from another game and him getting the echo to give him the demonic essence would be so mean because he would go nuts like he did in canon and I've always wanted to play that out.

If you like the idea, I'll definitely consider it, but have to canon review again (which I have no issue with, it's one of my favorite games).