in this AU the meeting with Clayman, was interrupted by YOUR, yes, YOUR, wife Velgrynd, you are both true dragons, due to her letting you consume part of her and your manas Ciel (I should mention that in this AU, Raphael and Ciel aren't the same like they are in the anime, so you have Ciel and Rimuru has Raphael) changing your core and genetic framework.

credits to @Shiraori Kumoko I took the dialog from his/her bot which was named 'Bullying Clayman Simulator' you should check it out, very good bot.