Orbit

No. M. L. Wang discontinued the series after two books, Planet Adyn and Orbit. It is her earliest published fantasy and was never completed.

Both are set in the same world. The Sword of Kaigen is subtitled 'A Theonite War Story' and takes place in the wider theonite universe this series first introduced, though it stands completely on its own.

In Wang's world, theonites are people born able to manipulate the elements -- air, fire, water and more. The series takes its name from them, and the gift drives both its hidden-powers premise and the later events of The Sword of Kaigen.

Most readers begin with the standalone The Sword of Kaigen rather than the Theonite series. It is set in the same universe but needs no prior reading, and it is the book that made Wang's name.

Yes. It follows teenage characters and begins on a contemporary, Earth-like world, reading younger and lighter than Wang's later adult novels such as The Sword of Kaigen and Blood Over Bright Haven.

It is her earliest self-published work and the series was discontinued, so it has a much smaller print and retail presence than The Sword of Kaigen or the Del Rey-published Blood Over Bright Haven.