In my opinion, a good team for the 7ds grand cross story would be centered around Meliodas. He is essential. Then add in characters like Ban for his ability to heal and his brute strength in combat. King can also be useful with his floating ability and area - of - effect attacks. And don't forget about Diane, who can deal massive damage up close. These characters together can handle a variety of situations in the story.
For the 7ds grand cross story mode, I'd say a solid team would be Meliodas, Elizabeth, and Gowther. Meliodas is the core fighter. Elizabeth is there for support with her healing and buffing abilities. Gowther can use his skills to change the flow of battle. For example, he can make enemies forget their tactics or create illusions. This combination gives you offense, support, and a bit of mind - game capabilities in the story mode.
The plot involves Rimuru's journey from being a rather weak (initially) slime to becoming a very powerful being. He meets many interesting characters. For example, there are the goblins he befriends early on. Rimuru helps them improve their living conditions. As the story progresses, he also has to deal with the threat of other more powerful monsters and even some human kingdoms that view his growing power with suspicion. In general, it's a story full of adventure, growth, and the forging of relationships in a magical and dangerous world.
It could also be an internal identifier used by a company or a group. Maybe it's related to a game or a fictional universe that is not associated with adult themes. For instance, it could be a level or an area in a science - fiction based game.
In 'cross sans x cross chara fanfic', a common theme is the exploration of the characters' backstories. Since both cross sans and cross chara have their own histories in the Undertale lore, fanfic writers might delve into these backstories to create more depth in their relationship. Another theme can be redemption. If either character has made mistakes in their past, the fic could focus on their journey towards redemption. And of course, there is always the theme of the relationship between the two characters, whether it's a platonic bond or something more complex that develops over the course of the story.