Not sure what you mean by "better"--the next book gets very heavily into Kiriel's past because a bunch of demons keep trying to kill Valedan, and the Ospreys are designated as his personal guard, and obviously her background is an asset. Basically for her the arc of the story is very heavily involved with the ring she picked up in this book--the question of her humanity is very much a live one, and the ring's agenda is to keep her two halves in balance. So, for instance, in the next book she sweats for the first time in her life. I think she does also get more likable, and also more easy to empathize with, as we realize what she endured. She and Isladar have a particularly interesting relationship.

If you like Kiriel and the Southern characters, I'd urge you to keep reading; in a lot of ways the majority of the story is about them, and they get up to some really cool stuff by the end. Particularly starting in book 4, that one is really awesome--there is less Diora in book 2, mostly because it's mostly set in the North, but she's back in a big way from 3 on. And in book 3 we meet the Voyani for the first extended interval, awesome women ahoy!