Thank you for the tag @courageousbxast ! sorry for the delay in responding. I haven’t seen the last few episodes of Stranger Things yet apart from some spoilers I checked for Steve but I’m going to go with my main OC, Lucy Arlesford, for the epilogue.
After Vecna is defeated, I could see Lucy needing to put some space between herself and Hawkins, as well as her strange situationship with Steve. Lucy basically wants to start over somewhere else far away. There are also long unresolved issues with her family back in England that now need to be confronted.
I think her epilogue would then probably ultimately see Lucy building bridges with her family and studying at Oxford, with the goal of becoming a physics professor, developing her personal interest in dark matter. In regards to her relationship with Steve, they would finally at long last reach a point of realization they just can’t live without one another and he would turn up unexpectedly one day at Oxford to tell Lucy so, giving her the courage to admit she feels the same.


