Squad K debuted during the Superman: The Coming Of Atlas story arch of 2008, in which they confronted Superman and were defeated.
Their second appearance was amidst the New Krypton story arch, where they appeared alongside General Lane's anti-Kryptonian outfit due to the result of a "partnership" between the two.
The team were forced to take the criminal Reactron on a mission to arrest Nightwing and Flamebird for the supposed "murder" of Mon-El. However, once the squad got the two in custody, Reactron Killed Col. Perseus Hazard and several members of Squad K by General Lane's orders. Following their deaths, a new team was assembled and led by Sergeant Cloud, now loyal to General Lane.
Squad K possesses various futuristic weapons at their disposal. They have so far displayed/mentioned the following as a part of their arsenal:
Skinjanglers - bursts of concentrated lightning.
Screamers - high-intensity sonics.
Microcollider Grenades - ???
SubSonic Curtain - ???