Don’t Wake a Sleeping Serpent

After Harry Defeated Voldemort, He Got Betrayed by Everyone Around Him, He Was Declared a Dark Lord and Was Imprisoned in Azkaban, and When He Gets a Visit From Someone Very Special, He Gets a Chance to Do It All Again, Correctly This Time, He Doesn't Hesitate, and Goes Back to His 4-year-old Body, Ready to Live His Life Correctly This Time. Grey!Harry and Eventual Harem.