This is when you and/or a Sonic character adopt Kal-El aka Superman.
(Let me know if you want to change it to Marvel)

Scenario 1: You and (crush) found Kal-El in a pod alongside the road. You take him in as your son and name him (you decide his name).

Scenario 2: You and/or (crush) came from Krypton like Superman years ago. One day, Kal-El came to Mobius in his pod and you found him. After you find out this is Jor-El's son, you take him in as a son in honor of the great man.

Scenario 3: Make it up