Today's character on the couch is Siron, a 19-year-old in Taylor's fantasy novel. He never knew he father, but his mother said he reminded her too much of him, thus she didn't like him. Siron's biggest regret was accidentally killing his mother. He pushed her into a stove, and she badly burned herself, which he intended, but then she cracked her head open when she fell. Now he and his sister, who Siron would do anything for, are penniless and starving. Siron's entire motivation hinges around his sister, keeping her happy, healthy, and alive.
Taylor wants to know: What would make Siron's devotion to his sister more realistic? What would it take for his devotion for her to break? And what would it take for Siron to become someone who no longer cares for anyone but himself?
The first thing my mind went to when you asked what would make his devotion more realistic was one word: GUILT. If some action of Siron's had inadvertently harmed his sister, either physically or emotionally, then he'd naturally feel responsibility.
What if when he pushed his mother into the stove, she stumbled over Siron's sister, causing her to fall into the stove as well? Even a small scar at Siron's hand might give credibility to his extreme protectiveness.
You already would have the built-in guilt of having taken away her mother. Even though Siron didn't mean to kill her, he did intend to hurt her. Either way, he would be removing his sister's parent. She was favored by his mother, so it would stand to reason that his sister had a good relationship with their mother.
So for his devotion to break (I assume you mean to stop altogether), a blatant disregard for his sacrifices for her might override the guilt. Then you would have Siron's emotions switch to anger, which is a secondary emotion. His true inner emotion would be more like disappointment or worry or fear (for her safety or even that of his own). [Click on the picture to the left to enlarge it. I use this in therapy all the time.] If his sister were to somehow fly in the face of his protection, or to somehow put them in further danger--that might make Siron question his utter devotion, and possibly help him live more for himself than solely her.
Hope you've enjoyed your time on the couch! If you want to go deeper, I'd be glad to have a longer session! Just click here.