The theme of redemption can also be present. Suppose Peter tells Erik about a wrong that Erik unknowingly did in the past. This could lead Erik on a path of redemption, trying to make up for it. Or it could be the other way around, where Peter is seeking redemption from Erik by telling him the truth about something.
One common theme is friendship. They often show how Erik and Peter form a strong bond despite their differences. Another theme is adventure, where they go on exciting quests together.
A prevalent theme is heroism. Erik is depicted as the hero in these fanfictions when he saves Peter. Also, the theme of redemption can be seen sometimes. If Erik has made mistakes in the past, saving Peter can be a way of redeeming himself. In many of these fanfictions, the journey of Erik to save Peter is also about self - discovery. He learns more about himself and his capabilities during the process.
One popular theme is their friendship. Writers often explore how Peter and Erik, with their different powers and personalities, form a bond. Another theme could be adventure. They might go on missions together, using their abilities to overcome various challenges. And there's also the theme of self - discovery, as they learn more about themselves through their interactions with each other.
One good place to start looking for 'Peter tells Erik' fanfiction could be Archive of Our Own (AO3). It has a large collection of fanfics across various fandoms, and you might be able to find some great stories there with that specific scenario.
There's also the theme of sacrifice. Sometimes Erik sacrifices his own desires for Christine's happiness, and vice versa. It adds a layer of depth to their relationship. And the exploration of their different social standings, with Erik being an outcast and Christine being a more 'normal' part of society, is another common theme in these fanfictions.
Love and passion are very common themes. Since lemon often implies a certain level of romantic or sexual tension, these fanfictions usually explore the deep love between Erik and Christine in a more intense way.
Redemption is also a theme. Sometimes Erik has done things that he regrets, and Charles is there to help him find a way back. Or vice versa, where Charles makes mistakes and Erik is the one to offer support. This theme of forgiveness and growth is quite prevalent in many Charles x Erik fanfictions.
Love and redemption are common themes. Since Erik has a troubled past, in many fanfictions, Christine's love redeems him. For example, in some stories, he learns to be more open and less vengeful because of her love.
One common theme is redemption. Erik often seeks redemption for his past actions through his relationship with Christine. For example, in many stories, he tries to prove that he can be a better person because of his love for her.