They are Called...

Ryu was more than a little bit annoyed, but he chose to let it slide. 

The truth of the matter was that he absolutely hated putting his life in the hands of others. A large part of the reason he was here in the first place was precisely because of that. Who else would choose to challenge a Throne when they had the full support of a Dao Sovereign like Aika? 

In truth, Aika treated Ryu no differently from how she would a disciple. Who else could boast having had a Dao Sovereign hunt down meals for them? 

In a lot of ways, though, taking on a Master was similar to placing your life in another's hands. Setting aside the obvious about whether or not such a person would really have your best interests at heart, just allowing someone else to guide you in cultivation was as good as trusting them with your life.