Assassin Droid HK-51
As teased in the "Fate of the Galaxy" video on the official site, HK-51 (an apparent descendant of the sassy-talking HK-47 droid from Knights of the Old Republic) appears to be a companion available for all classes (both Republic and Empire). He is reportedly found on Hoth.
"Prejudice... set to maximum."
There is a Codex entry for HK-47:
This HK-series assassin droid achieved infamy just before the Jedi Civil War. Although outwardly resembling a Systech Corporation unit, he was actually built by Darth Revan as a method of silencing political opponents. HK-47 has had many masters besides Revan, as well--corporate figures, crime lords, Hutts and Mandalorians--who have tried to harness his assassination protocols, usually with disastrous results.
Three centuries ago, after being found and repaired by the Jedi Exile, HK-47 helped defeat the Sith Triumvirate. After the fighting ended, he was kept in trust by the re-formed Jedi Order, much to his dismay; with the galaxy still in turmoil, the Jedi were concerned that HK-47 would start "helpfully" removing troublesome individuals. Then, during routine maintenance, an engineer accidentally activated an unknown command in HK-47's systems. Soon after, the droid disappeared from Jedi custody and left for deep space.
The Jedi's records claim that HK-47 has been destroyed and rebuilt several times since his creation. Darth Malgus's agents are said to have recently recovered HK-47's components from a mysterious facility built into an asteroid. Now reassembled and upgraded, HK-47 has become one of Darth Malgus's most formidable weapons.
All the data listed here may be incomplete or subject to change at any time. Damage numbers in particular should not be relied upon, as they are dependent upon level, gear and other factors. If you see something that is missing or incorrect, feel free to correct me.
|Armor Proficiencies||Passive||-||-||1||HK has the ability to equip heavy armor, and may also equip a Power Generator or Shield Generator.|
|Weapon Proficiencies||Passive||-||-||1||HK has the ability to equip a Blaster Pistol or Blaster Rifle.|
|Attack||Instant||1.5 sec||50m||1||Commands the companion character to attack your target.|
|Passive||Instant||1.5 sec||-||1||Commands your companion to stop fighting and follow you.|
|Sell Items||Activation: 5 sec||0||-||1||Sends your companion away to sell all low-quality items in your inventory to a vendor.|
|Deploy Shields||Instant||2 min||-||35||Reduces all damage taken by 25% for 12 seconds.|
|EMP Blast||Instant||15 sec||4m||23||Discharges an EMP blast that deals  energy damage to up to 5 targets in an 8-meter radius and weakens them, reducing the damage they deal by 5% for 6 seconds. This ability generates a very high amount of threat.|
|Flameguard||Instant||15 sec||8m||17||Releases a burst of fire that deals  elemental damage and increases the companionís armor rating by 20% for 15 seconds. This ability generates a high amount of threat.|
|Flaregun||Instant||1 min||30m||29||Draws in the attention of all enemies within 15 meters, forcing them to attack the companion for 6 seconds.|
|Frag Grenade||Instant||12 sec||30m||13||Hurls a frag grenade that deals [56-106] kinetic damage to up to 3 targets.|
|Charged Shot||20 sec||30m||1||A powerful electrical blast that deals [X] damage over 3 seconds.|
|Guard Stance||Instant||1.5 sec||-||1||Initiates Sentry Process, increasing armor rating by 60%, threat generation by 100% and shield chance by 20%.|
|Distract||Instant||20 sec||30m||1||Distracts the target, forcing it to attack the companion for 6 seconds.|
|Sniper Sight||Instant||1.5 sec||-||11||Enters Sniper Sight mode, increasing all damage dealt by 5% and lowering threat generation by 25%.|
|Grappling Line||Instant||15 sec||10-30m||9||Tows the target to the companionís location and generates a high amount of threat. Does not work against targets in cover. Does not work against players or bosses.|