Mehdi's Links
Tarani is his older cousin. Naga families are very complicated, and Mehdi doesn't like most of his. But the exception would be Tarani. If Mehdi gets into trouble, he'll go straight to Tarani. He doesn't know anyone else who would stick up for him with no string attached.
If Tarani had a favorite relative, which he doesn't admit to, it could very well be Mehdi. There's something about the kid that he just likes. Maybe it's that he's so quiet, and Tarani can talk freely. He has a tough time saying no to him.
Mehdi is strongly against having a romantic attachment to Rikin. He might be known to share his bed (after all, Rikin has silk sheets) and accept a bribe or two, but he would never relinquish his heart.
Mehdi is Rikin's obsession. If he could, he would spend every waking hour in Mehdi's company. Then again, part of the allure is that he can't have the naga. So who knows.