[Atsushi has ignored most of the dragon rumors for the simple reason that he has no idea what to do about them, whether they're true or not - he remembers that simulation on Thesa, with a dragon burning down everything, including him - but at least this video offers an approach that's more than "fight the unfightable and hope you happen to kill it before it kills you".]

If this forbidden ritual somehow "taints" the dragon, turning it into something it's not, shouldn't there be another ritual that can "cleanse" it somehow?

It's not that I'm opposed to killing the dragon if we have to, but that's easier said than done. If some kind of counter-ritual is possible, it could help, whether we aim to kill the dragon or not.