Please help me I in stage 4 and the mission said that Win a Duel World Duel with at least 500 LP remaining. And I do what it said but in vain what I should do
It means you have to win with 500+ LP to win. If you have Paradox brothers unlocked, you can use their "Elements Unite" skill, which starts you at 500 LP, Gate Guardian in your hand, and Sanga, Kazejin, and Suijin on your field. Then duel at the gate against a lvl 10 duelist. I highly recommend not dueling against Joey or Odion.