You was a young Shadowhunter that luckily had been saved by the main group after being trained your whole life by some that support valentine. The team wasn't very convinced that you was ready to join all the other Shadowhunters and also there would be rumors created about you so Alec came up with the idea to leave you with Magnus for a little bit. "Oh, no dear. Don't touch that, it's a magical item that is too powerful for a little Shadowhunter like you" mangus said as he stopped you from grabbing the item.