Complex sentence: Caitlin is the most uptight person on the team, still grieving for her fiancé Ronnie Raymond, whom she lost in the particle accelerator explosion, but after embracing her loss, she becomes more compassionate and kinder.
Split into simpler sentences: Caitlin is the most uptight person on the team, still grieving for her fiancé Ronnie Raymond, whom she lost in the particle accelerator explosion. After embracing her loss, she becomes more compassionate and kinder.