Gonzo is an antagonist in Breaking Bad and it's prequel Better Call Saul. He is the brother-in-law of Tuco Salamanca, and although he has no issue selling drugs alongside Tuco, he is far less bloodthirsty and violent.
Better Call Saul
When Cal Lindholm and his brother Lars conned Tuco's grandmother, Gonzo was tasked with bringing their other conspirator Jimmy McGill (who later went on to become Saul Goodman) back to the car. He witnesses Jimmy talk Tuco out of killing the brothers.
Gonzo is present when a deal between Tuco and Jesse Pinkman goes bad and sees Tuco beat Jesse severely. When Walter White confronts Tuco with the intention of avenging his partner, Gonzo joins his boss in mocking Walt and is shocked when Walt blows up Tuco's headquarters. Following this, Tuco enters into an uneasy partnership with Walt and Jesse.
At another meeting, No-Doze unintentionally insults Tuco, who starts beating him severely. Walt feels sorry for No-Doze and tries to stop Tuco, but Gonzo holds him back so he won't get himself killed. No-Doze dies, which Tuco blames on Walt and Jesse. Gonzo was visibly saddened, but disposed of the body under Tuco's orders. Gonzo later tries to move the body to give No-Doze better treatment, but the stack of cars where No-Doze's body was shifted and crushed him, causing him to bleed out and die.