Complex sentence: A descendant of a samurai family, Shutaro often carries a katana with him, which at any moment could be flying at Ataru's face, who has become adept at blocking it with his bare hands.
Split into simpler sentences: A descendant of a samurai family, Shutaro often carries a katana with him, which at any moment could be flying at Ataru's face. He has become adept at blocking it with his bare hands.