Do certain species hate each other?
Oh of course!
Humans generally don't like anyone. And are very much pro-human. Unless those humans are mages. Then FUCK those guys too. But also, they don't like it when a human comes from another kingdom either. So, fuck THOSE GUYS TOO. And then there are those humans who have children outside of their species. So what if they found love and happiness? FUCK EM.
It's really just a list of middle fingers all around.
Sirens tend to dislike those above land because of what they did to their Foremothers, The Benvarrey. Some do go to the surface to make a life for themself, but the process can be fatal. Those land dwellers are considered to be traitors and their children, the Merrow, to be demon spawn.
Drakes are the children of dragons. The original thieves. Many of the other races view them to be monsters just like their fathers. However, there are Cities and Villages near the border that tolerate them at the most. Drakes tend to view others of their kind favorably. Something you'll see more of in chapter four.
Aveles are one of the few races not treated with immediate distrust or hatred- outside of the Naga. They are excellent hunters and warriors whose main mission is believed to be rather honorable: defeat the rot of the eternal night and bring back their god, Uldor, back to life.
Naga are a wild card. Their race is so few that it's hard to have a real answer. However, they are the most inhuman looking of the other races. So many fear them. Their children, the nag'i are treated like Drakes. Just because they sorta look alike to the average human. Naga don't truly care enough about the other races to form an opinion.
Mages can be born of any of the races (save the Naga/Nag'i). They are generally seen as monsters with powers not meant for their bodies. Since magic is so volatile it is usually forbidden to be used. However, since the rise of the Witch Queen in the Bridge Isles, more and more mages have taken the chance to make a name for themselves.
Gavanthi, Lilibuel, titans, Gods, and Godlings are feared by the other races. To each other, all they see is another meal in their bid for power.
The only race liked by all the races is the Dwarva, masters of the rock and sea. They just do their own thing. The Dwarva view the other races as childish and too weak for their own good.