Natsu would also be an interesting choice. Natsu's brash and impulsive nature could contrast well with Mystogan's more reserved and calculated personality. They could start off not getting along but then grow to respect each other during a difficult quest.
One exciting moment could be when Natsu first unleashes his most powerful Fire Dragon Slayer attack against Laxus. The sheer power of the flames and the look of determination on Natsu's face would be thrilling. Another moment might be when Laxus counters with his Lightning Dragon Slayer magic, creating a spectacular display of light and energy as the two elements collide.
In my opinion, Natsu would have a good chance of winning. Natsu is known for his incredible determination and his ability to keep getting back up no matter how tough the fight. His Dragon Slayer magic gives him great power and his Fire Dragon's Roar can deal significant damage. Also, his experience in various battles has toughened him up. However, Laxus is no pushover either. He has his Lightning Dragon Slayer magic which is extremely powerful. But Natsu's never - say - die attitude might just tip the scales in his favor.
A fanfiction like 'Mystogan's Broken Spirit' could exist. This might detail how the events in the main series, such as the chaos in the Magic Council and the threats from other dimensions, gradually break his spirit. It could show his journey from a strong mage to someone on the verge of losing hope.
Another way is to join Fairy Tail - related fan communities on social media platforms like Reddit or Discord. Ask the members if they know of any good Mystogan hurt fanfictions. They might be able to recommend some great ones based on their own reading experiences.
In such fanfiction, Natsu might be depicted as more passionate and impulsive than in the original work. His fiery nature could be emphasized in a romantic or more intense context. Laxus, on the other hand, may be shown as more brooding and powerful. His strength and dominance could be a key part of the relationship dynamic in the fanfiction.
The potential for a unique relationship. Since they are from different versions of the same world in the Fairy Tail universe, there's a lot of room for creativity in a fanfiction. Writers can explore a romantic relationship, a platonic friendship, or even a rivalry that could turn into something more. The fact that they both have powers and abilities that can complement or clash with each other also adds to the allure of fanfictions about them.
You can start by looking on popular fanfiction websites like Fanfiction.net or Archive of Our Own (AO3). These platforms have a wide variety of fanfictions, and you can simply search for 'Erza Knightwalker x Mystogan' in their search bars. There might also be some fanfiction communities on social media platforms where fans share their works or recommend good ones.
One common theme is adventure. Since they are both from the Fairy Tail world which is full of adventures, fanfictions often put them together in new and exciting quests. Another theme could be friendship development. They might start as acquaintances and gradually become closer friends or even more.
His guildmates would surely be main characters. For example, Natsu could be there. Natsu might be really confused at first but then would be super protective of baby Laxus. Another could be Lucy. She might be the one who is more practical in taking care of the baby, like making sure he has proper clothes and a comfortable place to sleep.