Grenda is a high-ranking member of the Dwarven Black Guard, a military and police force with a strong presence in Keldagrim, where the Battlefield is located. She answers to Supreme Commander Bisi and, prior to the completion of Forgiveness of a Chaos Dwarf, Commander Veldaban. Grenda seems to have great respect for Veldaban, and, in the King of the Dwarves quest, she continues to address him as "Commander" in the Barendir tunnels though he has resigned his position. When Veldaban tells her to stop calling him Commander, she pretends not to hear him, and effectively puts him in charge of the First Regiment soldiers dispatched to Barendir to deal with the Red Axe army.
When you speak to Colonel Grenda in the battlefield she says, "Come on, you sons of trolls! D'you want to live forever?". This is a reference to Lieutenant Jean Rasczak, and by extension, Lieutenant John Rico in the sci-fi movie, Starship Troopers. This in turn is a reference to the phrase also uttered by Frederick II of Prussia to encourage his troops after having been defeated in battle.
Veldaban compares Colonel Grenda with Colonel Grimsson saying that the newer recruits of the Black Guard think she's a slave driver, but that Grimsson was still ten times worse prior to his discharge from the Black Guard following the Battle of Barendir.