One common theme is friendship. Many fanfics explore how Sonic and Shadow can overcome their differences and become friends or at least allies. Another is the concept of redemption, especially for Shadow who has a complex past.
A 'Metal Sonic x Shadow Fanfic' might explore an interesting dynamic between the two characters. It could involve their unique abilities interacting in different scenarios. For example, Metal Sonic's robotic precision and speed combined with Shadow's chaos powers could lead to some really intense action scenes. Also, the fanfic might delve into their personalities, perhaps showing a rivalry or an unexpected alliance.
One common theme is the idea of friendship evolving from rivalry. Sonic and Shadow start as foes but in many fanfics, they gradually become friends or at least respect each other more. For example, in 'Sonic and Shadow: A New Understanding', they learn about each other's motives and start to see the good in one another.
Adventure is also a big theme. The baby versions of Sonic and Shadow often go on exciting quests. They might be looking for a lost item, exploring a mysterious place, or trying to defeat a villain, which makes for really engaging stories.
In the 'sonic loves shadow fanfic' realm, 'Twilight Encounters' is quite remarkable. It sets a rather unique backdrop where Sonic and Shadow are stranded on an unknown island. As they struggle to find a way back home, their bond grows stronger, and the fic explores their growing affection in a very detailed and engaging way.
I'm not very familiar with specific 'sonic and shadow gay fanfic' stories. However, you can try searching on some popular fanfic platforms like Archive of Our Own. They have a wide range of fan - created content, and you might be able to find some interesting ones there.
There are quite a few. 'Sonic and Shadow: Parallel Journeys' is an interesting one where their paths cross in unexpected ways. It has a lot of action and character development. 'Shadow's Quest with Sonic' is also worth checking out. It takes the two on a journey that tests their limits and reveals new aspects of their personalities.
The lemon aspect, of course. This usually involves some form of romantic or sexual tension between the two characters. It can range from subtle glances and unspoken feelings to more explicit scenes, depending on the writer's style and the rating of the fanfic. But it's what gives the 'lemon' part of the genre its name. Also, the setting often plays a role. It could be set in the familiar Sonic universe, or sometimes in an alternate dimension created by the author to explore their relationship without the constraints of the main storyline.
Possible themes in a 'Metal Sonic x Shadow Fanfic' include loyalty. Metal Sonic is often loyal to Eggman, but in this fanfic, his loyalty could be tested when interacting with Shadow. Friendship could also be a theme, although it might be an unlikely friendship given their natures. They could start off as enemies but gradually come to respect and perhaps even like each other. And then there's the theme of redemption. If Metal Sonic has been used for evil in the past, could Shadow be the one to make him change his ways?
They might combine their powers through a sort of energy transfer. Shadow could transfer some of his chaos energy into Sonic while he's in Werehog form, enhancing Sonic's already formidable abilities. This could also work the other way around, with Sonic sharing his Werehog - specific energy with Shadow to give him new skills or boost his existing ones.