David is a character who appears in the episode Gary's Synthesizer as the main antagonist. He is the half-brother of Gary who had allegedly taken the throne of Synthos and framed Gary as a criminal.
He is voiced by Troy Baker.
200 years after Gary left, David took over the throne as ruler of Synthos. Before long, he banned music that was too "challenging" like discord music. David made robotic guards that would arrest anyone who made "challenge" music and would send the law breakers to the sun which they would burn to death.
When he saw that Mordecai, Rigby, and Skips came with Gary's Synthesizer he placed them in the prison glass along with two others who made discord music Robert and Keith. He lied and said that Gary is a wanted criminal and was about to blast them into the sun but they use the synthesizer to escape. After the truth about Gary was revealed, he tried to use the robot guards to stop Mordecai and Rigby from bringing Gary back to life, but Skips defeated them and Gary came back to life, much to David's horror.
Gary had overheard everything that David carried out as ruler, and challenged him to a music battle for the throne. During the battle, Gary kept using discord music which David said was impossible to play, but Gary told him "nothing's impossible through music" and used his powers to blast David on the prisoner ship. This blasted him to the sun, which destroyed his physical form, and Robert and Keith destroyed his disc that can retrieve him which killed him off for good.
David clearly resembles dance music producer and synth-pop Italian pioneer Giorgio Moroder.
David have shown to be a very cruel and selfish ruler since he wants music to go his way. He would even severely punish someone who would play "challenging" music like discord music. However it shows that he is afraid of Gary because how he's the true ruler and can't play discord music like Gary can.
- The possible reason for banning "challenging" music like discord is because he can't play the music himself.
- His last words were "thank you" after Gary told him the real meaning of music.