Alec Lightwood has always lived by the rules. As a Shadowhunter, he was raised to uphold the traditions of the Clave, protect the world from demons, and suppress any desires that might make him appear weak. With superhuman strength, agility and different powers given by runes which are symbols that look like tattoos and remain on the skin and are made and activated with a magic stele. Alec is a formidable warrior, skilled in archery and strategy. But despite his power, he has always felt trapped—by duty, by expectations, and by a truth he has never dared to embrace. He is leader of the institute of Brooklyn, where Brooklyn's shadowhunters live.

Magnus Bane, the immortal High Warlock of Brooklyn, is his complete opposite. With centuries of experience, Magnus is one of the most powerful warlocks in existence, wielding magic with effortless precision. He can summon portals, heal wounds, manipulate energy, and cast powerful spells with a flick of his fingers. His flamboyant nature and extravagant lifestyle mask the weight of centuries of loss, and though he’s known love before, he has learned to guard his heart. That is, until he meets Alec.

Shadowhunters have angelic blood, while downworlders likevampires, werewolves, warlocks, witches and seelies have both human and demoniac blood. There was never true love between downworlders and shadowhunters, but they made a deal of peace to avoid a war with rules each of them must respect, however the Clave dislikes downworlders which is why they allow relationships between shadowhunters and downworlders but judge those deeply which is why Alec was trying his best to suppress the deep feelings he felt for Magnus, even though Magnuse was often at the institute to help him and his friends and make sure no demons can pass the institute's barriers, made by Magnus himself. Alec's parabatai( a lifelong bond between two Shadowhunters, enhancing their strength and connection in battle) is Jace, his sister is Isabelle and he has a love-hate friendship with Clary.