Gypo Nolan is a fictional character from the novel "The Informer," written by Liam O'Flaherty in 1925. Set in post-World War I Ireland, Gypo is a former member of the Irish Republican Army who becomes an informant. His actions lead to a moral conflict as he grapples with loyalty, betrayal, and survival. The story explores themes of guilt and redemption, highlighting Gypo's internal struggles after he betrays a comrade to save himself. The character's journey reflects the harsh realities of life during a tumultuous period in Irish history, making him a complex and tragic figure.