I'm not entirely sure specifically what that particular 'Aichi Sendou Reverse Fanfic' is about as it could vary greatly. It might be a fan - created story that takes the character Aichi Sendou and puts a spin on his normal story, perhaps reversing his character development, relationships, or his role in the plot of the original work.
Well, start with the main platforms for fanfiction. AO3 is a great place as it has a very organized tagging system. Just search for 'Aichi Sendou' and then look for tags related to'reverse' or 'alternate version'. Another option could be some specific forums dedicated to the fandom of the work Aichi Sendou is from. People might share their fanfics there, including the reverse ones.
Their relationship can be developed through shared experiences. For example, if they are in a tough cardfight against a powerful opponent, they can learn to trust each other's moves and strategies. This trust can then spill over into their personal relationship.
One idea could be a story where Aichi and Kourin go on a journey to discover a rare card. Along the way, they face various challenges that test their friendship and cardfighting skills. Another plot could involve them getting trapped in a virtual cardfighting world and having to fight their way out together.
In << Full Time Expert >>, Lord Grim's height was 185cm.
While waiting for the anime, you can also click on the link below to read the classic original work of " Full-time Expert "!