The popularity might be due to the fact that both Link and Marth are well - known and beloved characters from different gaming franchises. Combining them in a yaoi relationship offers a unique and exciting take on their characters for fans who enjoy this genre. It allows for new and creative interpretations of their personalities and interactions.
You can try looking on some popular fanfiction websites like Archive of Our Own (AO3). It has a large collection of various fanfictions, including ones related to Link and Marth in a yaoi context. Just use the search function on the site and type in the relevant keywords.
One common theme could be friendship turning into something more. Since Ike and Marth are often friends in the original context, fanfiction might explore how that relationship deepens romantically.
Another option is to check out some of the dedicated Fire Emblem fanfiction forums. People there often share and recommend good Marth x Roy Yaoi fanfictions. They might also be able to give you some tips on finding new and interesting ones. Some of these forums have specific sections for different types of relationships in the Fire Emblem universe.
I'm not very familiar with specific ike x marth yaoi fanfiction. But you can try searching on some popular fanfiction websites like Archive of Our Own. There are often a lot of works about different pairings.
A great place to start looking for 'ike x marth yaoi fanfic' is on Tumblr. There are many fanfic writers who post their works there. You might come across some really interesting takes on the Ike - Marth relationship. Some fanfics might explore their relationship in a more angsty way, dealing with the difficulties of their positions in their respective worlds while still maintaining their connection to each other.
One common theme is the exploration of their unspoken feelings for each other. It could be about how they gradually realize their love in a world full of challenges.
Common themes in 'ike x marth yaoi fanfic' include loyalty and sacrifice. They are both characters with strong values, and in these fanfics, they might be willing to sacrifice for each other. Also, the theme of self - discovery is present. As they explore their relationship, they also learn more about themselves. For example, they might discover new aspects of their personalities that only come out in the context of their relationship with each other. This can be really interesting to read about as it adds depth to the characters.
Well, 'Marth and Roy: Unspoken Love' is a great read too. It starts with a chance encounter between them and gradually builds up their relationship. The author does a good job of creating a believable progression from friendship to something more. There are also some well - written action scenes in it that are related to their warrior - like natures.
It's quite possible on Fanfiction.net as well. Some writers like to create yaoi stories with a happy ending for this pairing. You might need to read through the summaries or reviews to find out which ones have a happy ending, as the site doesn't have as advanced tagging for endings as AO3. But with a bit of effort, you can surely find some.