Hotohori is a very lonely person. He has been alone since a young age and when he met Miaka, he hoped she would love him sincerely and not just because he was the emperor. It disappointed him greatly when she fell in love with Tamahome, but Hotohori didn't let it discourage him. He remains to Miaka a close friend and protector.
Hotohori is a loyal and courageous man who shows real concern for both his friends and his subjects. He can not stand to see anyone suffer and he takes the problems of others to heart and tries to solve them. He is very supportive and understanding and despite his feelings for Miaka, he wishes she and Tamahome well.
However, Hotohori will not tolerate anyone or anything that hurts Miaka and he has often been at odds with Tamahome over her. He takes his duty as her protector very seriously and he would gladly kill or die for her.
If you're wondering, yes, I am bitter. I think Miaka should have chosen Hotohori instead of Tamahome. Sure, he's a little conceited, but he's a good guy, dammit.
If you think so too, go visit the Hotohori Shrine