Soul blade developed a 3D fighting style that includes side dashing, just like Sea of Thieves. Making a tall tale surrounding Cervantes from the original Soul Blade/soul edge and the actual soul blade could be terrific.
Just that Rareware needs to partner with Namco, which is totally feasible.
The scenario could introduce an item that could serve as a way to engage into an advanced fighting mode with more fencing options, retaliation bonus after successful blocking and ways to fence the sword based on short and long presses of the attack button, and combos while dashing left, right, front, and fencing so that would make side slashes and front-dashing grand swings. Finally, sword dash, in that mode could be way less punishing in terms of recovery time.
The story of Cervantes in Soul blade was great. And the divide between him and the possession from the soul calibur was also epic. He's possessed by the sword, which makes him monstrous in the end. Quite epic.
