Akabayashi Mizuki doesn’t like drugs. He doesn’t like them so much, in fact, that when some kids taking after Dollars and using the net for their rootless drug-dealing operation set up shop in the bathroom of an Awakusu Group nightclub, he feels the need to impress the lesson upon said lads: drugs are bad. Don’t sell them. Don’t do them. Flush them down the toilet. They and their jonesing customers will be better off; he’s sure of it.
Why is he sure of it? Because drugs ended up killing the woman he loved, who happened to be Sonohara Anri’s mother, Sayaka. He fell for her when she slashed his eye with Saika six years ago, and though she had to refuse him because she already had a husband and family, her affection for her endured. When Sayaka’s husband became a violent drug addict (thanks to Akabayashi’s boss) and started abusing his family, including Anri, Sayaka killed him and herself, leaving Anri alone.
When his boss, a particularly nasty piece of human garbage, shares his plans to adopt and pimp out Anri, it’s too much for Akabayashi to bear, to the point that when Sayaka’s kid brother shows up to stab his boss, Akabayashi does nothing to stop it, and his boss’s death is a victory for all decent humankind.
These events six and five years ago transformed Akabayashi from the wild “red demon” he was known as to a far mellower fellow, and it’s not hard to see why: after spending so long on the side of the night, Sayaka showed him the day, and he liked it. Now, in the present, he walks the thin line between night and day, protecting not only Anri but Awakusu Akane as well; and never passes up a chance to teach misguided youths that they do not want to be walking in the night.