This is a oneshot on Dean's thoughts after Heart.
Hotel in North Dakota
There aren't a lot of memories Dean Winchester had of his mom, Mary. Heck, he had only been four when that yellow eyed son of a bitch had turned up of no where, slashed opened her abdomen, pinned her to the ceiling and set the world a light. Then again at least he had memories of Mary, Sam didn't. He didn't know the way Mary made all Dean's nightmares go away, the way she watched over him and kept him safe. The first time ever saw Mary in person was when he was twenty two and that was just her spirit.
Being a Winchester was tough, no point denying that. From the moment that that son of a bitch had killed Mary, Dean had been raised as a soldier. His dad John had taught him everything he knew, from how to kill an angry spirit to what bullets would kill a werewolf. Dean didn't resent being raised like that, it was who he was, what he was, a hunter of the supernatural, and a protector of innocents. Sam did resent it, but deep down knew that all those long nights waiting for John to come home after a hunt had made him who he was. It was the upbringing of a soldier that had kept Sam from joining the demon and fulfilling his destiny, that and Dean.
Dean had always wondered how different the special children would have been if they had a sibling to keep them from going dark side. Dean was the one after all that protected Sam no matter what, the one that joked with him when the world looked like it was coming to an end. Sure they had their fights but they were always there for each other. Dean was always there for Sam and nothing was going to change that. You didn't have to be a superhero to stick by your family and defeat evil on a daily basis.
Dean looked over at his kid brother, Sam. They were in an out of the way hotel in North Dakota. The hotel smelt bad, the bed sheets had stains across them and the bathroom looked like it hadn't been cleaned in a century. This was one of the worst places the brothers had stayed at and that was really saying something.
Dean suddenly got up in alarm as Sam jolted and rolled over in his sleep, face screwed up in pain. Another nightmare was attacking him. Dean could save Sam from the physical pain but he couldn't save his brother from the emotional side of it. He would give anything just to carry some of the weight, the visions, the pain and the over all dark ending in life.
Dean wished he could shield Sam from the nightmares, of Jess burning on the ceiling like Mary had, of John being punished in Hell for the deal he had made to save Dean's life, of Mary being killed in a wave of flames, and now of Madison, being killed by Sam when they couldn't save her.
Sam was strong though. Dean knew that and he was glad for it. Sam had the strength to save everyone and protect the world and he also had strength to do something that Dean could never do. Sam had the strength to kill Madison when she pleaded him to so that she could never hurt an innocent life again, Dean didn't have that. He couldn't kill his brother, not even if that was the only way to save the world. He couldn't.
Dean blinked as a single tear rolled down his face, he wiped it away and sat back down on his bed and began to get to work on saving Sammy.
Why? Because Dean was Sam's Guardian Angel.