In the game Armor Blitz, players assemble an army of anime “tank girls.” When the game debuted on Google Play in November 2016, it grossed just $23,400 in six months, less than half its production cost. Then the same game relaunched on the adult-gaming platform Nutaku—now with the notable addition of hentai cartoon porn. Blitz went on to bank more than $160,000 in six months. The thriving erotic-gaming industry that originated in Japan is now going global.

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