The D9 class cruiser, known in Klingonese language as Z'gal-class or Seeker class[1], was a 23rd century Imperial Klingon starship type, a medium cruiser[1] class in Klingon Defense Force service around the 2260s decade. (FASA RPG module: Klingon Ship Recognition Manual)
Service history and specifications[]
The D9 class medium cruiser variation, also named Z'gal (Seeker) class in its initial configuration, was derived from the D7 class battlecruisers that served at the forefront of the Klingon Empire in the mid-23rd century. (FASA RPG module: Klingon Ship Recognition Manual)
This was a sister class to the D9 class battlecruiser, which was known as the Devil-class. (Last Unicorn RPG module: Star Trek: The Original Series Core Game Book)
Around 2270, the KDF also deployed a battleship named the D9 class. (STO - Agents of Yesterday mission: "The Battle of Caleb IV")
At the time, the frequently upgraded D7 class was remained the Empire's flagship type. (TOS novel: Agents of Influence)