Grombrindal, known as the White Dwarf to his fellow longbeards, is now available as free DLC to all Total War: Warhammer players. He’d previously been a ‘timed exclusive’ tie-in with Games Workshop (mostly White Dwarf magazine, but the shops were giving out codes too), but is now freely available.
He doesn’t automatically download, you need to head over to the relevant Grombrindal DLC page and click the ‘download’ button. That will open up the Total War: Warhammer launcher, but should also add the DLC to the list of ones you own in the Steam library. Next time you load up the game, Grombrindal will be available as a playable Legendary Lord for the Dwarfs.
Here’s a run-down on his backstory, in video form.