From Frank Herbert's original series, some suggestions why this might be the case -


  • In Heretics of Dune, Lucilla is described as resembling his biological mother, and Lucilla resembles Darwi Ordrade (an Atreides) who apparently resembles Lady Jessica

Supporting reasons:

  • He is from Geidi Prime originally
  • He is employed in the breeding programs of Leto II and the Bene Gesserit repeatedly.
  • The Bene Gesserit program valued the Harkonnen genetic line, while Leto II describes Idaho as more Atreides than the Atreides (and the Atreides have Harkonnen blood via Jessica)
  • He has the black hair and green eyes that Paul Atreides has
  • Not sure it's an answer, but could be added to supporting reasons: dune.wikia.com/wiki/Hayt_De_Vries In the game Dune 2000, the Baron's Mentat is Hayt De Vries, a ghola. When Duncan is brought back as a ghola by the Bene Tleilax he is named Hayt and has mentat abilities. Clearly it's not canonical, but it is possibly a connection, though perhaps one the game forced. I know Hayt de Vries isn't Harkonnen but it is a connection I thought I'd mention.
    – Joshua
    Commented Feb 23, 2016 at 4:05
  • To be fair to the point on Idaho's use in the breeding programs, Leto II says it was to occasionally add a bit of primitive blood back in. This gives the impression that he's of incidental breeding stock, not intentional stock. The ghola allowed Leto to dip back in time.
    – user15742
    Commented Mar 23, 2019 at 1:02

2 Answers 2


While it is possible that Idaho is a distant descendant of a Harkonnen, there is no canon reference to this being so. Nor are there any real hints; I'm honestly surprised you read it that way, though it is an interesting possibility. Leto II merely means that Idaho takes the Atreides notions of morality more seriously than the Atreides themselves did, and the use of him in the breeding program is explicitly described as a "wildcard" by Leto II himself in God-Emperor of Dune, introduced specifically due to its unpredictability when combined with the relatively well-traced Atreides line.

The black hair and green eyes are hardly uncommon - I have them myself - and are probably due to the fact that Idaho was originally supposed to be from Caladan. Herbert seems to have forgotten which of his two Swordmasters was which in later novels.

This is a very good first question.

  • "Idaho was originally supposed to be from Caladan". Is that said somewhere? I know Gurney was from Geidi Prime, established early on.
    – user15742
    Commented Mar 23, 2019 at 1:06

In House Atreides, it said his parents were murdered in front of him. His parents were slaves of the harkonnens, but I don't recall it saying their bloodline.

from wiki Meanwhile, the young Harkonnen slave boy no. 11368, Duncan Idaho, is trying to escape the forests of Giedi Prime, where the na-baron Glossu Rabban is trying to kill him as a part of a game he and his friends are playing. Duncan finally manages to escape the planet, boarding a heighliner en route to Caladan.

if his parents had been harkonnen, would they have been slaves? I think not.

  • 2
    I don't think the fact of Duncan's family being slaves is not entirely ruling out them being Harkonnen or remote relatives (e.g. descendants of an ancestor of the Baron). After all the Baron is not exactly known to be a sentimental kind of a guy. If it serves his needs or a greater scheme in his eventual rise to the throne I guess that he will be ok with some "family" members bite the dust. (On a side note, I am not sure how to treat the book "House Atreides" as a source.)
    – Ghanima
    Commented Feb 6, 2015 at 20:30
  • 1
    Slaves can have some bloodline of their masters, for example if at some stage some Harkonnen raped his female servant (so probably not Baron but for example his grandfather), and she have birth to a child and it was an ancestor of Duncan, there is a possibility that Duncan had some Harkonnen blood in his pool. Leto II would probably know it. Commented Jul 27, 2017 at 9:37

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.