The Psi Index is a system used by the Terran Confederacy and later the Terran Dominion to measure the psionic ability of terrans,[1] a PA Profile having to be established within nine months of birth for all children born within the territory of the former.[2] Under the Dominion, the same system was also used to measure the psionic ability of gestalts; protoss/terran hybrid soldiers.[3]

People with low levels of psychic power can often detect its use,[1][4] and some can even resist telepathy.[4] A PI rating of 4.5 is too low to reliably project thoughts, and a person with that low a rating is not referred to as a "teep."[5]

The PI score was completely readjusted after Sarah Kerrigan was brought to the new Ghost Program, as she had reached unheard-of levels, forcing this change.[6] With a PI of 10, Kerrigan has the most powerful psi index on record, closely followed by Nova Terra (also with a PI of 10).[7]


PI Description
1-2 No psychic powers. Most humans.
2-5 Limited powers. Can sense other psionics. Wranglers.
5-8 Telepathy. "Teeps". Most ghosts fall between 5 and 6.
8-10 May have telekinesis. "Teeks". Extremely rare.[1]

Known RatingsEdit


An adjutant rated Queen of Blades as a "class 12 psi signature."[14][15] A gameplay trailer for Heart of the Swarm listed her as a "class 11 psionic."[16] After being reborn in primal form, an adjutant rated her power as "the highest psi ever recorded" considering it unclassifiable. [17]


  1. 1.0 1.1 1.2 1.3 1.4 1.5 DeCandido, Keith R. A. (November 28, 2006). StarCraft: Ghost: Nova. Simon & Schuster (Pocket Star). ISBN 978-0743-47134-3.
  2., Ghost. StarCraft Compendium. Accessed on 2009-07-11
  3. 3.0 3.1 Elder, Josh (w), Ramanda Kamarga (p), Angie Nathalia (i), Junadi (i). "Do No Harm." In StarCraft: Frontline: Volume 3 (paperback binding), pp. 48-89. Tokyopop, July 14, 2009. ISBN 978-1427-80832-5.
  4. 4.0 4.1 Furman, Simon (w), Federico Dallocchio et al. (p, i). "StarCraft #4" StarCraft 1 (4) (September 16, 2009) DC Comics (Wildstorm).
  5. 5.0 5.1 5.2 DeCandido, Keith R. A. (w), Fernando Heinz Furukawa (p, i). StarCraft: Ghost Academy: Volume 1 (paperback binding). Tokyopop, January 1, 2010. ISBN 978-1427-81612-2.
  6. Blizzard Entertainment. 2010-07-24. Cast of Characters: Kerrigan. Blizzard Entertainment. Accessed 2010-07-24.
  7. 2017-03-14, StarCraft on Twitter. Twitter, accessed on 2017-03-16
  8. 8.0 8.1 Blizzard Entertainment. 2013-01-22. StarCraft II Creative Development Q&A - Part 13. Blizzard Entertainment. Accessed 2013-01-22.
  9. 9.0 9.1 Kenyon, Nate. (September 27, 2011). StarCraft: Ghost: Spectres. Simon & Schuster (Pocket Star). ISBN 978-1439-10938-0.
  10. Ghost Profile: Delta. Ghost Profile: Delta, accessed on 2016-03-24
  11. Ghost Profile: Stone. Ghost Profile: Stone, accessed on 2016-03-24
  12. Ghost Profile: Pierce. Ghost Profile: Pierce, accessed on 2016-03-24
  13. Zahn, Timothy (November 8, 2016). StarCraft: Evolution. Del Rey Books. ISBN 0425284735.
  14. Blizzard Entertainment. StarCraft II: Wings of Liberty. (Activision Blizzard). PC. Mission: Wings of Liberty, The Moebius Factor (in English). 2010-07-27.
  15. Blizzard Entertainment. StarCraft II: Wings of Liberty. (Activision Blizzard). PC. Mission: Wings of Liberty, All In (in English). 2010-07-27.
  16. SCLegacy. 2011-05-30. 2011 Heart of the Swarm Gameplay Trailer . Youtube. Accessed 2011-08-17.
  17. Blizzard Entertainment. StarCraft II: Heart of the Swarm. (Activision Blizzard). PC. Mission: Heart of the Swarm, With Friends Like These... (in English). 2013-03-12.