God-Devouring Serpent and Rykard are two optional bosses you battle back-to-back in a single encounter in Elden Ring.
Although one of the demi-gods mentioned in Elden Ring’s introduction, Rykard is actually an optional boss similar to Starscourge Radhan, which can help you on the critical path if you prefer.
Otherwise, Rykard is a key part of the Volcano Manor quest – which is required to access – as well as a requirement for the Patches quest.