Velryna, your aunt is a pervert
Have you ever drifted away from someone? Lost contact with that person and, when you reunited, exchanged topics, experiences, and the feeling of emptiness they left was completely erased simply by their return to your life? Now, erase that from your memory and put yourself in Dante's shoes.
He lost several things completely when he was controlled by "evil", if we can call the corruption that passed through all natural defense systems that.
His great perception? Completely nullified, allowing himself to be hit, or rather, protecting Valentina at all costs, which also had some interference, preventing her from having any reflex; even so, it was his fault.
His great intuition? Nullified. He couldn't distinguish if what hit him was malevolent.
His protections? They didn't exist. The title of Hero didn't work, his pseudo-demonic body didn't resist, his numerous magical layers that Morgana placed in mental control, completely evaporated.