Mantis Type B

[deathunter]

Take no prisoners! - Kill the crew of 20 ships by sector 6 in the Mantis Cruiser.

Does it mean i need to kill 20 crews until i leave sector 6? or just IN sector 6 ?

[Alblaka]

By sector 6.
If you're playing the ship right, it shouldn't pose a problem.
One of my Mantis boarder managed to rack up 30 kills by himself in a whole game, which means he probably had ~22 by sector 6... ntm my other 3 boarders

Just board pretty much every ship (but Auto-Scouts), eventually get a rocket weapon and fire a salvo at their weapon system if necessary.
Try to get Tele 3, Medbay 2-3 and Defense Drones asap.

[Gorlom]

Take no prisoners! - Kill the crew of 20 ships by sector 6 in the Mantis Cruiser.

Does it mean i need to kill 20 crews until i leave sector 6? or just IN sector 6 ?

until you leave sector 6.

at least that is what "by" means in the federation cruisers "diplomatic"-something achievement.

[UltraMantis]

To get the achievement you have to capture 20 ships using boarders. Crew kills don't count.

If the description is accurate it has to be done in the first 5 sectors (before entering s6). This is probably not as difficult as it sounds, capturing ships is so natural for both Mantis cruisers.