In this, the final part of our Q&A with a Blizzard loremaster, Brian Kindregan, co-lead writer of StarCraft II: Wings of Liberty and lead writer of Heart of the Swarm, answers more of the community’s most burning lore questions.

Question: Are there any differences in the kind of mental/psychic disciplines the Protoss castes/tribes possess, be they martial, work-related, or used in daily life?

Answer: There are three castes: the Khalai (workers/civilians/scientists), Templar (military), and Judicator (government).

While the Protoss abandoned tribal affiliations with the advent of the Khala, Protoss descending from certain tribal bloodlines generally do have proclivities toward their historic roles. Below, I'm listing the tribes that we've heard of in various places in StarCraft lore. There may be other tribes among the castes, and we simply have not encountered them yet.

• Among the Khalai caste, the Furinax tribe is known for being scientists.
• Within the Templar caste, the Akilae tribe is considered the strongest. Artanis is a descendant of the Akilae. Descendants of the Sargas tribe are known for their stealth and assassination skills. There are three other tribal bloodlines in the Templar caste—the Venatir, Velari, and Auriga—but little is known about them beyond the fact that the Auriga are involved in the operation of the fleets. Urun has been their leader as of 2503.
• Among the judicators, we know of two tribes: the Ara and Shelak. The Ara were the leaders of the Protoss under the Conclave. Aldaris was likely an Ara. The Shelak tend more toward scholarly pursuits.

Question: The backstory to the Colossi mentions an additional race known as the Kalathi, who were almost wiped out by the Protoss when they used these war machines. Is there any additional backstory or information about this race (e.g., their state of technological advancement, their current situation, or why the Terrans appear to have no knowledge of them)?

Answer: There’s a substantial reference to the Kalathi in the "Mothership” short story. But that's really about it. The Terrans don't know about the Kalathi because they are located far outside the Koprulu sector. The Protoss were interfering in their affairs during a time of Protoss expansion. And as to the Kalathi's current state . . . well, the Protoss kind of knocked them back to the Stone Age. So, I would not expect to hear from them anytime soon.

Question: The psionic level of Kerrigan is 12. Compared to Kerrigan, what level are other units that can use psionic energy, like the Ghost, High Templar, and Archon?

Answer: The psi index rating (PI) was developed by the Confederacy, so the only beings that have been reliably measured with it are Terrans. It goes from 0 to 10.

Between 0 and 2, there is no noticeable psionic ability. (I'm a 1, personally.) At 3 and above, a person is considered "sensitive" to telepathy but is not a telepath. (The wranglers for the Ghost program are usually around 3.5.) PI 5 is telepathic, which also happens (surprise, surprise) to be the minimum acceptable rating for Ghost training.

PI 8 is potentially telekinetic, although PI 8s have been known to exhibit other outstanding powers. PI 8 is very rare. Nova is a PI 10. The only other PI 10s on record are Sarco Angelini (superintendent at the Dominion Ghost Academy) and pre-infestation Sarah Kerrigan. There is no data on how Spectres rate while under the influence of Terrazine.

Terran equipment refers to the Queen of Blades as class 12 because it can't measure her PI rating at all. She exceeds the scale and is at least an order of magnitude above 10.

Question: How large are the Hyperion and other Battlecruisers?

Answer: Their crews range from 5,000 to 7,000.

The only Battlecruiser we've ever given hard stats to is the Bucephalus, which was a new class of Battlecruiser, far bigger than anything previous. (Mengsk needed an impressive flagship to replace the stolen Hyperion!) The stats are below. Enjoy!

BUCEPHALUS TD
Imperial Flagship
Commissioned: 2503
Origin/ Manufacture: Ursa Shipyards/ Procyon Industries
Dimensions:
Length: 550m
Width: 82.4m
Power: Class 10 Fusion
Armaments:
16 J23Ship-to-Ship Missile Launchers
25 Crew-Served Batteries
145 Point Defense Systems
Air Wing: Variable
Ground Ordnance: Variable
Shield: Active for Warp and Orbital Insertion
Crew: 8,239
Range: Variable; Standard Equip: Koprulu Sector
In-System Speed: 1 AU per Cycle

Question: How does the Sound team for StarCraft II produce the Zerg sounds?

Answer: This isn't lore, but I forwarded this question to our awesome sound designers. This is what they said:

The original inspiration for Zerg sounds was from older science fiction movies. We try to give each unit or character a unique voice within the Zerg faction, but still keep them distinctly Zerg. So we always keep in mind that these are hive-minded, grotesque creatures, often cunning and insidious. We generally combine processed sounds of animal and human vocalizations, while movement sounds typically have a goopy slime/slither element. Finally, we always try something more experimental and not entirely obvious. These experiments often fail, but they are totally worth it on the rare occasions we hit a goldmine!

The sounds will change depending on the camera position. Top-down RTS view, or up-close cinematic? No matter the format, the sounds must resonate with the designers on an emotional level, and they must serve gameplay. Sometimes these two aesthetics will clash, and the designers must find a way to serve both. But at Blizzard, gameplay always comes first.

Question: Ask anything?! Alright, then, here goes . . . When is Legacy of the Void coming out?

Answer: Oh, that's easy! It's <redacted by Blizzard Public Relations>. Also, here are a few spoilers: the big secret is—hey, who are you? What are you doing in my office? Leave my computer alone! Is . . . is that a gun? Hold on . . . Wait a sec—

If you’re looking for more lore, here’s part 1 of our StarCraft II Creative Development Q&A, part 2,  part 3, part 4, part 5, part 6, part 7, part 8, part 9, part 10, part 11, and part 12. Thanks to everyone who submitted a question to Brian, except maybe that last guy, and look for us to do this again sometime!