Romance anime contains a broad spectrum of emotions, including drama, love, longing, and tragedy. While most romance shojo stories are light-hearted and comedic, even shows like Ouran High School Host Club can have something dark lurking in the background. Not all shojo characters are happy-go-lucky innocents. When romantic stories have sad themes, the culprit is usually either the male or female protagonist's disturbing past.
Source：https://www.cbr.com/most-tragic-shojo-romance-anime-boys-origins-ranked/
