regarding sequel story ideas and thoughts Part 1
I love the PTSD idea, I think it fits really well. I also like that he does bad things because of the PTSD. But I think that having him go full evil, reforge Caliburn and ending up being killed by Jack undermines the original story's premise that Claw is good. It would make his changes and fighting against Caliburn worthless and shallow. Now, what you could do is write those as nightmares that Claw and Jack have together (where they have the same nightmares at the same time), caused by Claw's PTSD, that they talk about and fight through to keep from happening. That way you get to write whatever you want but still keep the redemption aspect. Just my two cents.
Another idea, if you are open to it, would be the princess eventually reinstating Claw after he conquers his PTSD. I totally understand why she banished him, and it makes logical sense. But by having Claw fight through the PTSD and further proving his true loyalty, I could also see the princess seeing that as evidence of a true change of heart and as grounds to reinstate him as a knight, even if only ceremonially (with the red feather of course but not the power, or just change the feather color).