So, in a way, Nappa does the most damage in the show. I give him the credit for Yamcha's death(even though saibamen off him. But he planted the damn things), Chaotzu blows himself up and fails to take Nappa with him, right before he was gonna plow him in jagged rocks, rips Tien's arm off and he dies after another failed, yet admirable attempt, and last but not least kills Piccolo/Kami with that lethal mouth fireball. Hell, he paralyzed Krillen and woulda got Gohan if Goku didn't show up. Not to mention wiping off the military/media during his 3 hour break.
No one say Buu, that doesn't count since there in him.
No one say Buu, that doesn't count since there in him.