I'm not sure specifically what the 'lissa graphic novel' is about as there could be many with that name. It might be about a fictional character named Lissa and her adventures, or it could deal with themes like friendship, love, or a struggle against some sort of adversity. Without more context, it's hard to say for certain.
Since I don't know the exact 'lissa graphic novel', I can only assume that Lissa is likely to be one of the main characters. There may be other characters like her friends, maybe a sidekick who helps her on her adventures, or perhaps an antagonist who creates problems for her.
Perhaps the fanfic delves into an adventure where Frederick and Lissa are partners. They could be facing various challenges together, and through this, their bond strengthens. For example, they might be on a quest to save their kingdom from an evil force. In this scenario, their individual skills and abilities come into play, with Frederick being strong and brave and Lissa having her own unique powers or knowledge that contribute to their success.
Another element is their roles in the kingdom. Chrom as the exalt and Lissa as a healer. Fanfics play with these roles, such as when they have to use their positions to protect the kingdom from threats. They might make strategic decisions together, which showcases their combined leadership.
I don't know who Spin Evans is in this context as the 'spin evans gay story' is not widely known. He could be the author of the story, or perhaps a character within it.
I really liked 'Lissa and Rose: The Unseen Adventures'. This fanfic takes the two on a journey outside of the normal Vampire Academy setting. They face new challenges together, which makes their friendship even stronger. The writing is quite engaging and it's easy to get lost in the story.
There's also 'The Meeting of Hearts' which is a really engaging 'lucina x lissa fanfic'. It focuses on how they first meet and the initial spark of their relationship. It has a really nice flow and the dialogue is well - written.
One possible aspect of Christian and Lissa's relationship in fanfiction could be how they support each other through the challenges in the Vampire Academy world. Christian, with his unique position as a Moroi with an unusual power, and Lissa, the Dragomir princess, might find solace in each other's company. They could be shown exploring their powers together, like Lissa using her spirit ability and Christian his fire power in tandem to overcome threats from Strigoi or political intrigue within the Academy.
You might find that the fanfic creates new storylines for them. Maybe they go on a journey to discover a lost treasure or solve a mystery. In these new storylines, their characters will be developed further, and you'll see different sides of them. For example, Frederick might show his more vulnerable side when faced with difficult decisions during the adventure, and Lissa could prove to be more resourceful than expected.
Sam Evans in 'sam evans first time fiction' is a mystery. He could be an aspiring writer who is making his first foray into fiction writing. Or he could be a fictional character in the story, with his own unique backstory and personality. We just need more information to be certain.