The son of Worf and K'Ehleyr, who was raised by Worf's adoptive parents.
Alexander Rozhenko is the son of Worf and K'Ehleyr in The Next Generation. Worf does not know he has a son until K'Ehleyr brings the boy aboard the Enterprise in Reunion. After she is murdered by Duras, Worf sends Alexander to live with his adoptive parents, Sergey and Helena Rozhenko, on Earth.
Alexander later returns to live with Worf aboard the Enterprise-D. He has little interest in the warrior traditions his father values, and their relationship is often tense. In Firstborn, a Klingon named K'mtar arrives to train him and is revealed to be Alexander himself from the future, trying to change history because in his timeline he became a peacemaker rather than a warrior and Worf was assassinated.
In Deep Space Nine, a young adult Alexander enlists in the Klingon Defense Force and serves aboard Martok's ship during the Dominion War, where he and Worf begin to repair their relationship. He is later welcomed into the House of Martok.