Tenel Ka Djo is a female Hapan Jedi Knight, daughter of Prince Isolder of the Hapes Consortium and the Dathomiri witch Teneniel Djo. She was raised in both traditions — Hapan court politics on one side, Force training and physical discipline on Dathomir on the other — and joined Luke Skywalker's academy as a teenager. She is a central character of the Young Jedi Knights series (1995–1998) by Kevin J. Anderson and Rebecca Moesta, and is Legends only.
The friend group that ran the 1990s
Young Jedi Knights put her alongside Jacen and Jaina Solo, Lowbacca and Zekk, and for a generation of readers that cohort was Star Wars. Tenel Ka is the group's severe one — literal-minded, allergic to comfort, and the only one with a constitutional crisis waiting at home.
Queen Mother
She eventually takes the Hapan throne, which puts a serving Jedi at the head of a sixty-three-world great power — a conflict of interest the later novels mine hard. Her long, secret relationship with Jacen Solo, and their daughter Allana, become the emotional centre of the Legacy of the Force sequence.
Continuity
Legends only. Nothing in current canon corresponds to her, to Hapes as depicted here, or to the Dathomiri lineage she comes from — canon's Dathomir, via The Clone Wars and Asajj Ventress, is a different construction built on some of the same raw material.