One interesting plotline could be Roman teaming up with the main characters against a new common enemy. Maybe he has some inside knowledge that could help them defeat this powerful foe.
Another plotline could involve Roman surviving but being hunted by a secret organization. He then has to rely on the RWBY team for protection while also trying to figure out why this organization is after him. This would create a lot of tension and interesting interactions between Roman and the team.
Obviously, the RWBY team - Ruby, Weiss, Blake, and Yang - are often involved. Ruby might be the most likely to initially trust Roman if he shows signs of changing. Yang could be more skeptical, leading to some interesting conflicts.
One possible plotline could be Pyrrha dealing with the trauma of the near - death experience. She might struggle with PTSD and have to work through her fears in order to get back into the fight. Another plotline could involve her relationship with Jaune. Since she survived, their relationship could develop further, perhaps leading to a more romantic connection. She could also become a mentor to the other students, using her own experience to help them grow and become stronger fighters.
Maybe in the fanfiction, Peter survives the snap but his powers are affected in some strange way. He has to figure out how to control his new - or rather, altered - powers while also coping with a world that has been turned upside down. This could involve him teaming up with some unexpected allies.
One possible plotline could be Anakin's redemption taking a different turn. Instead of dying, he lives and uses his newfound Light Side strength to help Luke rebuild the Jedi Order. He could become a mentor to the new generation of Jedi, sharing his experiences and knowledge, which is a far cry from his previous role as Darth Vader.
One interesting plotline could be Bardock using his newfound chance at life to train and become an even stronger warrior. He might then use his power to protect planets that were previously doomed in the original story. Another could be Bardock interacting with characters he never got to meet before, like certain Earthlings, and learning about their ways of life and fighting styles.
Maybe in the fanfiction, Lee teams up with some unexpected characters. For example, he forms an alliance with a group of loners who have unique survival skills. Together, they build a fortified community and start to develop new ways of living in the post - apocalyptic world.
Another plotline could involve Rock getting stranded in a strange and dangerous new world within the fanfiction. He has to figure out how to survive using his existing skills and also discover new powers or allies along the way. For example, he might meet a group of robots who have different values than the ones he is used to, and he has to find a way to work with them to get back home.
One interesting 'rwby roman torchwick fanfiction' could be about his early days as a criminal. It might explore how he got involved in the seedy underworld and formed his crew. Maybe it shows his first big heist and how he started to gain a reputation.
A great plotline might involve the deaged characters interacting with their younger selves' memories. Weiss could be haunted by her family's expectations in a new light, as if seeing them for the first time all over again. This could lead to her making different choices and growing in a whole new direction.
One possible plotline could be a character sacrificing their own powers to save their friends from a powerful enemy. For example, Ruby might give up her Silver - eyed Warrior abilities to stop Salem's latest scheme and protect her team.