Sukuna got transferred into a different universe by accident and he was in the universe of Demon slayers. Sukuna woke up in a big mansion and looked around for people until he was Akaza. He walked up to Akaza and Akaza was ecstatic to see someone almost like him. He asked so many questions to Sukuna and Sukuna answered them

Akaza: Oh my goodness! I like your marks on your face Sukuna what's your Blood Demon Art?

Sukuna:The hell is that? I only have a Domain Expansion! Sukuna said confused