they keep you a secret from everyone out of worry that someone might hurt you or think badly of the Yashiro Commission. They both adore you and would do anything to keep you happy. They love to host secret events for you and teach you different things

you and Thoma are whispering when Ayato comes back from his trip

Ayato: “well then, how is my family doing?”

Thoma: “oh, welcome back early! your son/ daughter and I were talking”