Erza is another character that is frequently involved. Her strong and disciplined nature with her requip magic makes her a prime candidate for a swap. Imagine her swapping magic with Jellal. It would not only change the way they fight but also add a new layer of complexity to their relationship and the overall story.
Natsu and Gray are often popular choices. Their contrasting personalities and magic types make for an exciting swap. Natsu's fiery and impulsive nature combined with Gray's ice - make magic or vice versa can lead to some really interesting stories.
Lucy is also a popular character in these types of fanfictions. Swapping her celestial spirit magic with someone like Mirajane could create a whole new set of adventures. Lucy's more inexperienced and learning - based approach to magic compared to Mirajane's more experienced and powerful magic could lead to some great character development.
One interesting concept could be characters swapping their magic powers and how they adapt to it. For example, Natsu with Erza's requip magic would be really cool. He might use it in a more brute - force way compared to Erza.
Natsu is often a popular character. His fiery nature and strong loyalty make him a great candidate for love - centered stories. The 'blood' part could be related to his dragon - slayer heritage, which might play a role in some kind of blood - magic or a connection to an ancient dragon bloodline that ties into a love story.
Natsu Dragneel is often very popular. His hot - headed and determined personality makes him a great protagonist in fanfiction. He has a strong connection to his Fire Dragon Slayer magic which can be explored in many different ways.
Gray might also be involved. Since he has his own rivalries within the guild, in some fanfiction, these rivalries could cross the line into bullying - like behavior from either side. And then there's Lucy. As a new member initially, she could be on the receiving end of bullying from those who are more established in the guild in certain fan - created stories.
Definitely Natsu. He's always getting into trouble with his brash actions, so he's a prime candidate in punishment scenarios. Then there's Lucy. She's new to the guild in a way and still learning the ropes, so she could easily find herself on the receiving end of a punishment. And of course, Makarov, as the guild master, is often involved in doling out or dealing with punishments for the members of Fairy Tail.
Natsu could be one of the main characters. Given his love for food, he might be really interested in an eclair in a fanfiction. He could be on a quest to find the most delicious eclair in the Fairy Tail world. Another could be Lucy. She might use her celestial magic to help in a story related to an eclair, like finding a magical eclair that has been hidden by a celestial spirit.
Obviously, Happy is one of the main characters since it's about his death. Natsu would also be very involved as he and Happy are really close friends.
Natsu is often involved. His powerful fire magic could be a key factor in either trying to stop the destruction or, in some cases, accidentally causing more chaos if his power goes out of control. Gray, with his ice magic, might be there to counterbalance Natsu's heat or work together with him to face the threats.
Natsu is often a popular character in these fanfictions. His energetic and fearless nature makes him a great mentor or big brother figure to an adopted character. He can teach them about the importance of friendship and determination in the world of Fairy Tail.
Obviously, Ace himself is a very popular character. His backstory from One Piece and his potential interactions with Fairy Tail characters make him interesting. Natsu is also popular in these fanfictions as he and Ace could have a great dynamic, given their similar personalities in terms of being hot - headed and powerful.