Ertegun is a famous and flamboyant DJ residing on Mars, where the anime Carole & Tuesday is set. He is a young adult male with gray hair cut to ear length and green eyes. When first introduced, he is portrayed as a quintessential celebrity archetype: self-absorbed, surrounded by admirers, and living a lavish lifestyle in a mansion, often accompanied by beautiful women. His public persona is built around a massive ego and a signature catchphrase, Who am I? which he uses to command attention and affirm his own status.

Despite his initial presentation as a superficial party celebrity, Erteguns character possesses significant depth, rooted in a strong personal philosophy. In the world of the series, music is increasingly generated by artificial intelligence, a method championed by producers like Tao. Ertegun stands in stark opposition to this trend, embodying a staunch human-centric or human above approach to music creation. He openly dismisses AI-composed music, valuing the raw, organic expression that only a human artist can achieve.

Ertegun undergoes a major transformation after a sudden and dramatic downfall. He naively entrusts his finances to an AI manager, which ultimately embezzles all his money and leaves him completely bankrupt and homeless overnight. Stripped of his wealth, status, and the luxury that defined his existence, Ertegun falls into a deep crisis of identity. He becomes depressed, questioning his own worth and ability to make music without the symbol Ertegun that he had cultivated. In his lowest moments, he is shown wrestling with his own psyche, depicted as an internal battle between a good and a bad version of himself.

This crisis serves as a turning point. Rescued from the streets by his loyal former assistant, Roddy, Ertegun is forced to return to the fundamentals of his craft. He uses a simple keyboard, reminiscent of how a novice would learn, to reconnect with music on a purely emotional level. Through this process, he overcomes his inferiority complex and rediscovers his artistic passion, leading to a creative rebirth. He emerges from this experience with renewed purpose, recognizing that his identity and talent are not dependent on his material wealth or fame.

Throughout the story, Ertegun maintains key relationships that influence his actions. He has a close bond with Roddy, who acts as a grounding force and a true friend, supporting him during his bankruptcy and identity crisis without ulterior motive. Initially, his interaction with the protagonists Carole and Tuesday is negative; during their first meeting, he dismisses them and crudely suggests they are trying to sleep their way to the top, an insult that leads to a confrontation. This event establishes him as a difficult gatekeeper in the music industry. However, following his personal reinvention, he chooses to collaborate on a new song with Angela, the rival singer of the protagonists, demonstrating his continued relevance and passion for creating powerful, human-driven music.

Erteguns notable ability is his talent as a DJ and music producer. He is a successful superstar and a celebrated figure on Mars, which initially makes him an intimidating figure for aspiring musicians. His creative process is rooted in human feeling and spontaneity, rejecting the algorithmic precision of AI. The story shows that his strength lies not just in performance, but in his capacity for resilience, as he is able to rebuild his career from nothing by trusting in his own innate creative instincts.