With two new designs born out of the Heavy Corvette chassis, Tactical intelligence wondered what other weapons systems could be applied to the heavy corvette design. After observing the Frerrn preference for plasma-based weapons, one of the off-duty designers applied plasma bomb launchers to the corvette design. The plans were discovered the next morning by the design team fresh from the Missile corvette. With no assignments, they turned to perfecting this model to see if they could pull off another "garage kit" and replicate the success of the attack bomber.
Although the corvette mounts a weapons system larger than the one used on the older "Kaark" attack bomber, it seems the yield is no larger than it was on the previous model. The only difference is that reload time has been cut down dramatically by the installation of separate plasma drives into each of the weapons pods- giving the plasma corvette it's own supply of plasma independent of the main drives. This allows the ship to move at the speed of a corvette while having the same punch as an attack bomber.
When this reached the attention of Kuun-Lan's captain, he ordered a squadron produced out of curiosity's sake. A group of four were made and participated in trials... where it became apparent that the Corvette's one strength did not outset it's weakness. With the speed of a corvette, it cannot evade the guns of most typical assault frigates.
However, it's worth noting that the design was fielded in actual combat after Turanic Raiders ambushed Kuun-Lan. Desperate to get everything launched, the plasma corvette prototypes were put into battle where they quickly demolished closing ion array frigates- which had no defenses against strike craft. They even participated in the counter-attack against the Turanic Raider carrier. If nothing else, it has given second merit to the design and consideration for it's uses against capital ships.