In "Demon Slayer: Kimetsu no Yaiba," both Kyojuro Rengoku and Sanemi Shinazugawa are exceptionally skilled Hashira with incredible speed and combat abilities. However, Rengoku is known for his Flame Breathing techniques, which emphasize powerful and fast moves, while Sanemi, the Wind Hashira, also demonstrates incredible agility, especially in his Wind Breathing techniques.
While the manga and anime showcase both characters' abilities in unique ways, it's generally accepted that both possess remarkable speed and reflexes, making it difficult to definitively state who is faster. Their combat styles differ, which influences how they utilize their speed in battles. Ultimately, the comparison may come down to personal interpretation or the specific context of their encounters.