Igor is the long-nosed, mysterious master of the Velvet Room, a space that exists between dream and reality, mind and matter. His background is rooted in mystery; he was originally a doll brought to life by magical means, which has led him to ponder deep questions about his own existence and what it truly means to be human. This fascination with humanity drives his role as a guide and observer of those who enter his domain. In Persona 5 the Animation: Stars and Ours, Igor's situation is unique, as the character seen for much of the story is not the real Igor but an impostor.

The real Igor has a calm, courteous, and even-tempered demeanor, treating the protagonist with politeness despite his own striking and somewhat unsettling appearance. He communicates in a cryptic manner, often foreshadowing future events and offering insights into the protagonist's journey and the power of emotional bonds, but he rarely provides direct warnings or interventions. His core motivation is to guide guests of the Velvet Room, allowing them to prove their own potential and fulfill their contracts without his direct interference, as he believes humanity must demonstrate its own strength.

The true Igor's role in Stars and Ours is largely defined by his absence. Prior to the events of the story, he and his attendant Lavenza were attacked and imprisoned by the malevolent entity Yaldabaoth. This false god sealed Igor away, split Lavenza into the twin wardens Caroline and Justine, and assumed Igor's form to manipulate the protagonist from within the Velvet Room, which was transformed into a prison and relocated to the depths of Mementos. The false Igor, acting as an agent of Yaldabaoth, refers to the protagonist as a prisoner of fate and steers him toward a predetermined ruin while posing as a helpful guide. This deception is a central pillar of the anime's conflict. The real Igor, even while imprisoned, remains a passive observer and does not break his policy of non-interference, instead placing his faith in the protagonist's ability to see through the falsehood. The key development for Igor occurs near the climax, when the protagonist successfully fuses Caroline and Justine back into Lavenza, breaking Yaldabaoth's control and freeing the real Igor. Upon his release, Igor takes his proper place in the restored Velvet Room and confirms the wager he made with Yaldabaoth over the potential of humanity. At the story's conclusion, after the protagonist has fulfilled their contract, Igor uses the power of the protagonist's social bonds to forge a Persona of the World Arcana, a power capable of changing reality, a feat Igor himself admits he never expected to witness in his lifetime.

Igor possesses several notable abilities tied to his role. He is the proprietor of the Velvet Room and can grant access to it, change its appearance to reflect the state of the guest's heart, and provide vital services related to Personas. His primary functions include Persona fusion, which allows the creation of more powerful new Personas, and the Persona Compendium, a registry that allows previously obtained Personas to be recalled at will. He also possesses near-omniscient foresight, allowing him to comment cryptically on the path ahead, though he admits not everything is within his power to foresee. Finally, he holds the authority to bestow the ultimate power of the World Arcana upon a guest who has successfully completed their journey and forged strong bonds with others.