What's the Name of That Book??? discussion

Read 2-4 years ago. The story is told from two perspectives. One being the normal boy. I think he lives in a city and is possibly an apprentice to someone or lives with monk-like people as a rescued orphan. I think he finds a book about the previous world which is considered legend or myth. He joins a group of people trying to find this legend/myth (maybe the legend is people or a city). He travels with them. Meanwhile, the other perspective is of a girl, one of the "special" kids left on a floating(or just really tall) house & yard. Each kid has a special skill or power. I think they are the children of gods or aliens. The girl connects to the normal boy during the night via dreams. They talk and become friends, or more than friends. Eventually, the boys group reaches their destination but something goes wrong.

Spoiler:

Someone important dies in the end. They fall off the floating land or sacrifice themselves in order to fix whatever the problem was. I think it may have been the special girl, but I'm not sure.

Cover: I believe it was blue, because I think one of the characters has blue skin or their skin turns blue. It also may have shown the special girl, or whoever it was that died, falling.

Thank you for the help!

Strange the Dreamer by Laini Taylor?

Yes!!! That’s the book! Thank you so much!!!!!