This page contains information regarding Star Trek: Lower Decks, and thus may contain spoilers.
The kar'takin was a short polearm with a straight-edged blade and a stabbing point, favored by the Jem'Hadar for hand-to-hand combat.
During the Dominion War, captured kar'takins were kept aboard Klingon ships for training purposes. In 2374, Worf introduced this weapon to his son Alexander, attacking him with it as part of a training exercise. (DS9: "Sons and Daughters")