Love against all odds is also a popular theme. Given Erik's disfigured appearance and his dark past, their relationship is seen as something that defies the norm. Fanfictions explore how their love can overcome these obstacles.
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.
One common theme is redemption. Often, Erik is depicted as seeking redemption through his love for Christine. Another theme is the power of music, as it is a strong connection between them. For example, in many fanfics, Christine's singing can soothe Erik's tortured soul.
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.
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.
Love is a very common theme. It could be the unrequited love that Erik has for Christine at first, or the evolving love between them. Another theme is redemption. Fans often write about Erik's journey towards redemption through his relationship with Christine. Also, the idea of acceptance, like Christine accepting Erik for who he is, is quite common.
Redemption is also a theme. Erik, being a complex and often misunderstood character, may seek redemption through his relationship with Christine. Fanfictions might explore how he tries to make up for his past wrongdoings, such as his threats and manipulations in the opera house.
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 is a very common theme. It could be the unrequited love of the Phantom for Christine or a more mutual, yet complicated love that develops between them. Another common theme is redemption. The Phantom often gets a chance to redeem himself through his relationship with Christine.
One great 'Phantom of the Opera Erik x Christine Fanfiction' is 'Shadows of the Heart'. It beautifully delves into the complex relationship between Erik and Christine. The author really captures the essence of their characters, with Christine's torn feelings between her fear and fascination for Erik.