Breen royal turned outlaw who fled his people with his partner Moll and searched for the Progenitors' technology.
L'ak, played by Elias Toufexis, is a member of the Breen ruling family in the 32nd century, a nephew of the Breen Primarch Ruhn. He leaves his people behind and runs away with the courier Moll, and the two become partners in crime and in love.
In the fifth season of Discovery, L'ak and Moll steal a clue to the Progenitors' technology and race the USS Discovery to the rest of the trail. L'ak's Breen nature lets him change form and use powerful abilities in combat. He is badly hurt in a fight with Michael Burnham and taken aboard Discovery, where Federation medicine proves unable to save his Breen physiology, and he dies in custody. His death drives Moll to ally with the Breen against the Federation.
L'ak was one of the first Breen characters to be seen without their armor and refrigeration suits in Star Trek. His story brought the long mysterious Breen into the foreground of Discovery's last season.