
You can make fan fiction out of this idea.
The thought occurred to me... What if you took Zeref Dragneel from Fairy Tail and had him be the crush/love interest of one of the girls in Winx Club? Honestly, that'd be really interesting, since Zeref's personality is deep... I mean, really deep.
I know all the girls in Winx Club have their boys, except for Roxy; you can include Roxy in the options for Zeref, because that's totally fair.
Zeref is actually one of anime's most forgotten but complicated antagonists. Unlike many Fairy Tail characters like Natsu, Lucy, Gray, etc. who are base-breaking and get some criticism for braindead, questionable parts in their characterizations... Seemingly, the only people who hate Zeref are just braindead viewers, because Zeref is the kind of character where you have to be a sharp-thinker, carefully elaborating every little detail in his very deep personality. He is a character written for passionate viewers.
Oddly enough, Zeref's character was even more positively received outside of Fairy Tail fan base, with people saying he's an amazingly written character in the wrong series (not to mention the wrong kind of fan base), someone who deserves to be in an anime as passionately written as him, like his whole arc. Maybe it's because Fairy Tail is an anime that's not particularly deep compared to things like Fullmetal Alchemist or Attack on Titan, and since the fan base is relatively braindead, they get alienated by how Zeref is written so differently compared to pretty much every character.
Maybe if Zeref was in a series where almost all storylines are as grounded and passionate as him, this wouldn't be the case.
For how base-breaking Fairy Tail may be (often using typical Shōnen tropes like braindead moments, fan service, and Power of Friendship), Zeref was surprisingly written with a passion. Unlike how many Fairy Tail characters usually had some comedic moments or maybe not particularly dark or moody when trying to be serious, the author took Zeref's life experiences and overall character much more seriously, with every part of his arc being played as drama or shock factor.
Imagine if Zeref was the central antagonist of Winx Club (with no watering down his character), he'd make for Winx Club's most amazingly written antagonist, having a deep personality and being connected to the arcs of so many characters. He would also be handled better, since Fairy Tail's author rushed the arc where Zeref was supposed to shine.
[Zeref actually has an article in Incredible Characters Wiki that thoroughly analyzes 99% of his character, and this is especially helpful for those who still get confused by how deep his personality is.](https://greatcharacters.miraheze.org/wiki/Zeref\_Dragneel)