Duty.

Ryu was relentless. It felt that no matter how he did it or how much he did it, he simply couldn't be satisfied. As though the flood gates had opened, the tides rose endlessly, its limits impossible to spot. 

They say that the Dragon and Qilin races were among the most lustful beasts in all of existence, and Eska learned that first hand on this day. If it wasn't for the fact her current body was formed with Isemeine's strength as a base, she may have very well collapsed by the end of it all. 

… 

Eska silently sat before Ryu. Though her hands were in quite a precarious place, her actions weren't sexual any longer. Rather, they were delicate and caring as she washed Ryu's body. One would have never thought that she was a Sky God at that moment, she looked no different from a concubine caring for her husband.