Street Fighter IV seriesEdit
Mel appears with his parents in the prologue, the Masters family being invited to a party hosted by Karin. He is passed out most of the time sleeping, but awakens during Ken's fight with Karin.
Street Fighter III seriesEdit
A three year old Mel appears in Ken's ending, where he wishes to follow in his father's footsteps and trains with him. 
Ken is seen playing a video game with his son in his ending. This was Mel's very first appearance, predating Street Fighter III.
Eliza gets pregnant before the second Street Fighter tournament is announced (thus, earlier than in the games' timeline), and she and Ken soon get married. He is then born after the tournament.
In the OVA, Eliza has just found out that she's pregnant but hasn't told Ken yet. As she's getting ready to give him such good news, she is captured by C. Viper in order to lure Ryu in for Seth. In the end Ken manages to rescue her in one piece, and she tells him that he's going to be a father.