The dark shrine was formerly known as the dark obelisk. Its original conception was as a tower structure with defenses superseding that of the planetary fortress. It was later repurposed as a detection tower since design was testing the game with all the detection removed from the normal towers. Then it was cut from the game for a short time until the need for a Dark Templar building was required.
↑The Obelisk is the new name for the Dark Pylon, and the Dark Shrine is the new name for the Dark Obelisk. The Obelisk still has the probe buff, but now also acts as a shield generator, and still has Argus link to transfer energy as well. The cloak ability has been removed from the Obelisk. The Dark Shrine remains the same in function, allowing the production of Dark Templars. Karune. 2009-06-11. OBELISK question. Battle.net StarCraft II General Discussion Forum. Accessed 2009-06-11.