Sif, also known as the Great Grey Wolf, is a loyal companion to Artorias the Abysswalker in the Dark Souls series. Known for wielding a massive sword in his mouth, Sif serves as a formidable boss character players must face. His tragic backstory is intertwined with the fall of Artorias, as he guards his master's grave in the Darkroot Garden. Sif's role is crucial in illustrating themes of loyalty and sacrifice, as encountering him reveals deeper lore about the bonds between the game's characters.