The Kageyashi in Akiba’s Trip are no sparkling vampires. They’re a separate race of people (the characters go as far as to imply they’re a different species) who can only live with limited exposure to sunlight. They solve this problem by covering themselves up, dressing normally. This way, they can mingle with human society. If they’re stripped down to their undergarments in broad sunlight, though, they dissolve into ash and float away into the wind.
And now, you, as the protagonist, are now one of them.