So I was flying through the Mantis Homeworlds (sector 4) in the Engi B, looking for Kazaaakplethkilik. I already bought a teleporter and two Mantis, and I survived to that point (not really easy in the Engi B ). After a while I found him and beat up his ship a little, and then I teleported and finished him off. After that the 'find his stuff' quest beacon appeared 2 jumps away from me... First jump: a Mantis Fighter. I attempted to remain concealed, because this wasn't the first time I tried to unlock the Mantis cruiser and I really wanted to get to the beacon, but the ship spots and attacks me. He had a Burst Laser Mark II and two missile launcers (3 damage, I think), and one of the first things he hit were the weapons and the teleporter (so no attacking) Then I attempted to flee, but he hit my engines AND the helm! So a couple of shots later my ship was destroyed and I went to the forums to write my first post here (so frustrated!)...
Final quest marker had nothing to do with it... you unlock the Mantis Cruiser straight after the battle with Kazaak.
You either lacked the blue option to get it in the first place, or didn't choose it (hint: you want him to live).
). After a while I found him and beat up his ship a little, and then I teleported and finished him off. After that the 'find his stuff' quest beacon appeared 2 jumps away from me... First jump: a Mantis Fighter. I attempted to remain concealed, because this wasn't the first time I tried to unlock the Mantis cruiser and I really wanted to get to the beacon, but the ship spots and attacks me. He had a Burst Laser Mark II and two missile launcers (3 damage, I think), and one of the first things he hit were the weapons and the teleporter (so no attacking) 
Then I attempted to flee, but he hit my engines AND the helm! So a couple of shots later my ship was destroyed and I went to the forums to write my first post here (so frustrated!)...
