Alec and Clary - Being lost in the Shadoworld.
Alec in the beginning really doesn't like Clary as he sees her as a direct threat to the Shadoworld as she has been hidden from this world by her mother and this is an issue as she is the daughter, of Valentine one of the evil Shadowhunter's that saw the head of the Shadowhunter's the clave, as failing in there duties to protect the world from demons and this to him included downworlders. So half mundane creatures, or have demon blood. So creatures like fairies, werewolves, warlocks, and vampires. Valentine made a movement within the shadow hunters' world called the circle and recruited people to his cause. He saw that the "downworlders," were a threat and needed to be eliminated. Clary's mother was married to him and didn't see the signs of as they point out in the show him being a psychopath. So Alec from day one sees that she is a threat because she is Valentine's daughter, and his parabaiti, Jace is infatuated with him to the detriment of