Should let @Eben Stone answer first but when he said ultra aggressive, he really meant what he said. I already hesitate to recommend the Timeless Slim OC to others as it is fairly aggressive, and compared to the Knight Helmet it is like a foam sword compared to a katana. Soo... guess you are warned enough now.How is the blade rigidity? By looks, I am getting flashbacks of the Yaqi Katana which had zero blade support and the blade just rudely jutted out. It was incredibly efficient, but was rather scary to use.
To answer the question: The top cap bends the blade firmly so much that the blade is very stiff despite having no support from above despite it visibly sticking out a lot. You can make the Knight Helmet a lot milder by shaving shallow, it has a lot of leeway with the effective shaving angle.