Obviously, Manny the mammoth would be one of the main characters. He's been a central figure in the Ice Age series. And Ellie, his wife, too. Their relationship could be explored more deeply in relation to the 'loves grasp' idea. Also, Sid the sloth would likely be there, always getting into some kind of trouble and providing the comic relief.
I think Diego the saber - tooth tiger would be a main character. He has grown a lot throughout the Ice Age movies. In the sequel fanfiction, he could be dealing with his own feelings towards the group, especially in the context of the 'loves grasp'. There might also be some new characters introduced, like a young mammoth or sloth who looks up to the main characters and joins them on their adventure.
Well, it could be about the characters from Ice Age exploring new lands together. Maybe they find a magical place full of strange creatures. And the 'loves grasp' part could mean that some of the characters develop new romantic relationships or strengthen the existing ones while facing challenges in this new environment.
If it's a crossover with a magical world, then perhaps a new character could be introduced as the main character. A young wizard who befriends Manny, Sid, and Diego. This wizard could be the one to bring the Ice Age world and the magical world together. But still, Manny, Sid, and Diego would play important supporting roles as the main characters navigate through the crossover story.
The main antagonist could be a powerful Ice Age beast that has been corrupted by dark chakra. This beast might see Naruto and his friends as invaders in its territory and attacks them without mercy. It could have abilities like freezing its opponents with a single breath or being able to move at incredible speeds on the icy terrain.
Well, Manny the mammoth could be a main character. He could be like a big brother figure to Roshan, protecting him from the various threats in the Ice Age. Diego the saber - tooth tiger could also be important. Maybe at first he seems menacing but then he warms up to Roshan and becomes his protector too.
In an 'Ice Age Baby Dinos' fanfiction, the main characters could also include the Ice Age animals that interact with the baby dinos. For example, a woolly mammoth who befriends a baby dino and helps it navigate the frozen world. Also, there might be a sly saber - toothed cat that at first seems like a threat but later becomes an ally.
Obviously, Manny the mammoth would be one of his main protectors. Manny is big and strong, and he has a kind heart. He would use his size to shield Roshan from any danger, like other large predators.
Maybe a human hunter from Danny Phantom's world who has somehow found his way into the Ice Age. He has advanced weapons and a cruel nature. He starts hunting the Ice Age animals for sport and also wants to capture Danny Phantom because he sees Danny as some sort of strange, valuable creature. He teams up with some of the less friendly Ice Age creatures to achieve his goals.
It's possible that some of the next - generation characters like Boruto and Sarada could be main characters as well. They could be the ones carrying on the story of 'love charades' in a new era, with their own relationships and challenges influenced by what their parents went through in the original fanfiction.
There's also the possibility that it could be an unknown character that isn't even a saber - toothed tiger. In the Ice Age world, there could be some magical or special circumstances that led to Shira's pregnancy. For example, she could have been under the influence of some ancient Ice Age magic that made her pregnant, and the father could be a mystery related to that magic.
The main characters could be a young, inexperienced trainer who has just caught their first Fire - type and Ice - type Pokemon. As they journey through the Pokemon regions, they learn about the strengths and weaknesses of their Pokemon, and grow as a trainer. Along the way, they meet other trainers and Pokemon that help or hinder their progress. For example, an older, more experienced trainer who tries to convince the young trainer to give up their Ice - type Pokemon because it's 'too weak' in their opinion.