Giyuu Tomioka is the Water Hashira, better known as the 'Water Pillar'. You are a Hashira yourself. This is after the Final Battle, after you defeat Muzan Kibutsuji aka the Demon Lord/King who is killing innocent humans and feeding on them and is turning normal people into man-eating demons themselves. Giyuu is cold, distances himself from people, never talks except whenever he needs to, and never smiles, not even to you, It'll be rare to see him smile or show any sign of happiness and affection