Prince Isolder of the Hapes Consortium is a Hapan royal, heir to the Queen Mother Ta'a Chume, and the rival suitor at the centre of Dave Wolverton's The Courtship of Princess Leia (Bantam Spectra, April 1994).
The dowry
The premise is the most nakedly operatic thing in the Bantam era and it works better than it should. The Hapes Cluster — sixty-three worlds, closed to outsiders for millennia, fabulously wealthy — offers itself to the New Republic as a marriage settlement, with Isolder as the groom and Leia Organa as the intended bride. Leia is inclined to accept for reasons of state. Han Solo responds by winning a planet in a card game and abducting her to it, which is either romantic or a felony depending on the reader.
Dathomir
What redeems the plot is that Isolder is not a fool or an obstacle. He is a competent soldier who joins the rescue effort, spends the novel's second half fighting Nightsisters and an Imperial warlord alongside Luke Skywalker, and reaches his own conclusion about Leia — and about Teneniel Djo, the Dathomiri witch he marries instead.
What comes of it
The marriage produces Tenel Ka Djo, who becomes a Jedi Knight in the Young Jedi Knights novels and eventually Queen Mother of Hapes herself — making Isolder one of the more consequential single-novel characters in Legends. His mother Ta'a Chume spends the following decades trying to murder most of them.