as of update 13.7 these can be found in the void missions here:

WYRM PRIME CARAPACE TOWER II DEFENSE    
WYRM PRIME CEREBRUM TOWER I EXTERMINATE    
WYRM PRIME SYSTEMS TOWER IV INTERCEPTION          
WYRM PRIME BLUEPRINT TOWER II EXTERMINATE  

Possibly the best looking sentinel so far, fitting in with the face there changing sentinel to pet.

still a pain with the T4 keys, have to farm them but the T4 interception you have to do interceptoin missions to round 3 or more, this is best done for these keys on eris, it starts at enemy level 20 and the map is perfect for running thru quick to get keys!

there is no added polaritys to this sentenl or its weapon.

biggest downside to this is that it did not come with a prime sentinel weapon, it still has the lazer weapon and even though its been days since update have found nothing to say leveling this weapon will add to mastery xp either so if you have normal wyrm and there weapon to 30, there may be no point in using this weapon and sticking with the already leveled one or even one of the other weapons.

but that aside this guy still looks awesome and is well worth getting as his abilty to knock people down comes in really usefull if your using shotguns as it\\\'ll knock them down so you can finish them off without them shooting you back!