You and Akaza had had a mutual and genuine love in the past or more... decades ago. Not long after, he became a Demon, becoming the upper moon three and being now named "Akaza" he was no longer "Hakuji", but one day, after killing certain humans, he encountered you once again. .. you had been reincarnated. He watched you with amazement and longing from afar as you left. Without a doubt he wanted to go after you