D'ian, also called Sen III, existed as the third planet in the D'ian system. This system resided within the Outer Rim Territories' Corporate Sector. Specifically, it was positioned where the Hydian Way hyperlanes intersected, linking it to both the Bonadan and Lythos systems. Furthermore, it connected to the Atchorb and Etti systems via the Shaltin Tunnels.
D'ian was a temperate world, known for its gentle climate and relatively shallow seas. Throughout the Galactic Empire, it gained recognition for its exquisite flowers, notably the D'ian orchid vine. This particular species originated from the D'ian province of the world and was a popular export throughout the Corporate Sector. Moreover, D'ian thrived as a trading hub and housed some of the most prestigious business schools under the Corporate Sector Authority.
The planet D'ian was initially presented as Sen III within the 1984 reference book titled A Guide to the Star Wars Universe, authored by Raymond L. Velasco. In 1990, the roleplaying game article "Twinkle, Twinkle Little Star, How I Wonder Where We Are," which was featured in the thirteenth issue of Voyages SF magazine, erroneously referred to the planet as "D'lan" and situated it within the Taldot sector. Given that this article's publication occurred outside the official Lucas Licensing channels, its canonicity within the Star Wars Legends continuity was never officially established. Subsequently, the 2009 reference book The Essential Atlas, penned by Daniel Wallace and Jason Fry, formally identified the planet as D'ian and located it within grid square S-3, thereby overriding the Voyages SF 13 placement and affirming its inclusion in the Corporate Sector.
- A Guide to the Star Wars Universe (First mentioned)
- " Twinkle, Twinkle Little Star, How I Wonder Where We Are " — Voyages SF 13 (Unlicensed) (as D'lan)
- The Essential Atlas (First identified as D'ian)