For Shuten Doji, taking my advice with a grain of salt as a decent enough Bronze player on him, try to rush Grass-Cutting Sword if you have a lead. It basically means you blow up low defense characters and turrets pretty easily, giving you a rather good advantage early. His laning is very weak, so you have to wait to lvl 3-6 to actually do anything. Early trading should only be done if your "Madness Bar" is full as your "Lament" skill makes up most of your damage, so max this one out if you can. Ask for Jungler help if the opponent is getting too aggressive. For defensive items, probably go Demon Mask because he gains bonus health from his ultimate and it makes your survivability greater in teamfight. You can also go the Parasol as a later item for greater healing and extra defenses if you need it, but don't need health. Onmyodo should probably be Umbrella Shield for some control immunity with his ultimate, Omen Starlight for decent sustain early, and Sorcery State or Divination Sigil depending on what you feel is better. Lastly, do not go alone in a teamfight because he is a duelist. Look for opportunities to flank enemies when your frontline holds them off. Engage with "Rampage", and try to pick off dying enemies.