It could be Doji. He's always been after powerful beyblades and Gingka's Pegasus is one of the strongest. He might kidnap Gingka to get Pegasus and use its power for his own dark plans. Another option is Ryuga. Although he has his own code, in some fanfictions he could be desperate enough to kidnap Gingka to prove his dominance in the beyblade world. Also, a new and unknown blader who is jealous of Gingka's skills and popularity could be the antagonist and kidnap him to make a name for himself.
One plot idea could be that Gingka is kidnapped by a rival blader who wants to steal his special beyblade techniques. The rival could hold Gingka in an abandoned warehouse and try to force him to reveal his secrets. Another idea is that a group of evil bladers kidnap Gingka to prevent him from competing in an important tournament. His friends then have to search for him and rescue him before the tournament starts. A third plot could be that Gingka is kidnapped by a mysterious figure who believes Gingka has a hidden power within him and wants to harness it for their own evil purposes.
One possible scenario in this fanfiction could be that Gingka and Madoka start off as friends, gradually realizing their deeper feelings for each other during their beyblade adventures. For example, after a tough battle where Gingka is injured, Madoka takes care of him and they share a tender moment that makes them both aware of their love.
One possible fanfiction could be about Gingka and Madoka going on an adventure together to find a rare and powerful beyblade part. Along the way, they face various challenges and have to rely on each other's skills. Gingka uses his beyblade battling expertise, while Madoka uses her technical knowledge to repair their beys when needed.
In some fanfictions, Gingka and Madoka might time - travel back to the origins of beyblades. They learn about the history and secrets of beyblades together. This could involve meeting the very first bladers and getting involved in ancient beyblade battles that shape the future of the sport they love so much.
I'm not sure about the 'best' but there are many talented authors. Some authors who have a deep understanding of the characters and write engaging stories are often popular. You can check on fanfiction platforms like FanFiction.net or Archive of Our Own to find authors with high ratings for their Gingka and Madoka fanfictions.
Perhaps in the fanfiction, their love is a secret at first. They are both worried about how their friends in the beyblade community will react. So they keep their feelings hidden, stealing private moments together. But eventually, their friends notice the chemistry between them and support their relationship.
In a fanfiction, Gingka and Madoka having a baby could be portrayed as a new chapter in their relationship. It might show how they adapt to parenthood. Maybe Gingka would be the protective father, teaching the baby about beyblading values like determination and courage, while Madoka would be the nurturing mother, ensuring the baby is well - cared - for.
The plot could involve a tournament where Gingka and Hikaru are on different teams. However, they keep getting drawn to each other. As the tournament progresses, they find themselves having to team up against a common enemy. In the middle of this intense battle, they share a kiss that gives them the power and motivation to win. After that, they decide to explore their relationship further despite the potential challenges from their respective teams.
Another plot could be set in an alternate universe where Gingka and Madoka are from rival clans. They initially see each other as enemies but gradually realize that they have more in common than they thought. As they work together to solve a common problem that threatens both of their clans, they fall in love. This would be a story of enemies - to - friends - to - lovers, with a lot of beyblade battles in between to add excitement.