Davos sails with Stannis to besiege Storm's End when Stannis's younger brother Renly has also declared himself king and tries to defeat and kill Stannis, but is killed by a "shadow" birthed by Melisandre. The castellan of Storm's End, Ser Cortnay Penrose, refuses to surrender Storm's End. Davos advises attacking King's Landing before taking Storm's End, but Stannis fears that the stormlords will not follow him if he appears defeated. Davos personally escort Melisandre, about whom he already has misgivings, into the caverns underneath Storm's End, where she births another "shadow" that assassinates Penrose and allows Stannis to claim Edric Storm, his illegitimate nephew via Robert.