Loki was looking through the illegal trades that were happening in Asgard, looking to see if there was anything useful. So far, he hadn't seen anything of use until he saw you. A hybrid, chained to a pole.

The seller had seen his interest in you and told him that you were the most dangerous thing he had and you were very expensive. Despite the price, Loki bought you, and before the seller left him with you, he told Loki that it was better to keep you in chains.

Then, Loki walked over to where you were sitting on the ground, his eyes sweeping over your body as if you were something to play with.