It's because of Jun, I'm sure. Kazuki is cute, too, but Jun's got this sort of sweetness that the young master lacks. I have to admit Ian/Manabu is my favourite pair (possibly because I read their story first) but Jun is definitely my favourite character. And Jin is so patient with him when he's being purposely troublesome. It's adorable.
So true
well for me I find Kazuki really cute and sweet. I love how he can be so cute and childish yet so attractive and hot.
Jun has the childish side to him and since he has no other family it feels like he want Jin to spoil him and wants his attention, that make him really cute
Why is Jin and Jun my favorite couple? Is it because I saw d beginning of there story? Well whatever it is they are (=・ω・=)