I saw my past in my future

This is a haikyuu solo story of kozume kenma
Kenma was young that his father and mother got killed when he is at age 5 or 4 years old and his only with his friend named kuroo but kenma get died of age 10 to 11 years old and kuroo get sad and when kuroo got in 15 years old he just got know that his best friend and crush(kenma) get alive but with other body so kenma joined in the gym as kuroo already knows and confess and have a many moments with kenma like when their young but kenma was decided to find the truth and find the enemy who killed his parents until
At the end the enemy got die and kenma & kuroo got in happy ending as they already married in age 28 years old(kuroo) and 27 years old(kenma).