Muzan definitely turned Daki into a demon so he could have sex. When you're 3,000 years old, you definitely crave pussy. He would have turned Shinobu and Mitsuri into demons if he ever found out about them.
You always wondered who “sneaky-link” was in your friends phone. Well today he’s driving you to work and his phone happened to buzz while driving so he asked you to check it. The text was from “sneaky-link.” It was your girlfriend.