Jacen Solo is a human male, the son of Han Solo and Leia Organa and twin brother of Jaina. He was born in Timothy Zahn's The Last Command (Bantam Spectra, 1993), five minutes after his sister, and he became the central figure of the Legends timeline's last decade of publishing.
The philosopher
As a boy he is the one who collects animals and asks what the Force is for. As a young man in the New Jedi Order series he is captured, tortured and forcibly reshaped by the Yuuzhan Vong, and comes out of it with a mystical, unusually well-argued theology that other Jedi cannot follow. He spends five years afterwards travelling the galaxy studying Force traditions nobody else takes seriously.
Legacy of the Force
The nine-book Legacy of the Force series (Del Rey, 2006–2008) turns all of that against him. Convinced he can see a future catastrophe and that only he is willing to prevent it, he takes the title Darth Caedus and commits, in order, to surveillance, torture, murder and mass killing — each one justified by the last. It is the most thoroughly reasoned fall in Star Wars fiction, and the most uncomfortable, because at every stage his arithmetic looks defensible.
Legends only
Jacen exists only in Star Wars Legends. Current canon gives Han and Leia one son, Ben Solo, whose fall is faster, more emotional and considerably less argued. Readers coming from the sequel films frequently mistake Jacen for an earlier draft of Kylo Ren. He is not; he is a different thesis about how good people become monsters.
Reading note
Do not start here. Legacy of the Force only lands if you have read the New Jedi Order series first and watched what was done to him.
