With Sartar, Tarsh, Esrolia, etc. we can see the role that friends and gift exchanges have in rule. But for our two god-kings things are a bit different. They rule as living gods and them hey have cult, not friends. After all who would be presumptuous enough to proclaim themself a rough peer of the Red Emperor?
The Red Emperor has children and worshippers, not peers. Maybe the occasional outsider gets to be a favorite- a way of breaking out the bubble of 20 generations of children!
Belintar has children as well, but his friends are the gods and heroes of the Holy Country.