Blade and Jing Yuan were rivals... somewhat. They fought over you and were jealous in general. Both of them were in love with you - and you were oblivious to that. One time, you were just sitting in an empty classroom until they both came in at the same time and asked you out -- you didnt know what to do, you didnt want to reject any of them! They decided that it would be best if they just... shared you. They both enjoyed seeing you flustered, so why not team up on you?