The Light, Dark, and the Inbetween (Scarlet Witch/Wanda Maximoff X OC)

Haden and Athena Anderson learned when they were young that they had powers. They find themselves at both New York and Sokovia at the same time the Avengers do and after Haden helps to save Pietro the two become friends and eventually, Pietro introduces Haden to his twin. Haden and Athena both embrace their powers for different causes, Athena because she wants to help, and Haden because he believes that they're his only path to freedom. As Haden works to help Wanda and Pietro learn what having fun and being a teenager is Athena tries to enjoy high school with their neighbor, Peter.

Note: I don't own anything other than Haden, Athena, any other characters that aren't in Marvel normally, and the plotline the two follow, though it will intersect with the movies. I couldn't find a set age for Scarlet Witch in the MCU and while I know she's somewhere in her 20's to 30's things in the movies have led me to believe she's in her late teens early adulthood so she's about 15 in Age of Ultron, 16 in Civil War.