From Project Kurai Ryu:

Young Kai has been passionately idolizing Ginta ever since his heroic battle in the War Games of six years ago. Since then, ARMs have become a common thing, Guardians especially! Kai himself doesn't have one though, and dreams big of being able to get an ARM like Ginta's! When his caretaker, the old ARM-smith that took him in after his parents' deaths, sends him out on an errand, he is attacked by a bandit from "chess"! In his escape attempt, he finds more than he bargained for when he comes across Babbo! But, now with Babbo's awakening, the fake ARMs are going out of control! Is it Kai's turn to save MARHeaven following in his hero's footsteps?

Matsuri Ichimatsu, Haruno Koume, and Sanguubashi Takezou are old friends with one thing in common: despite their good looks, they're incredibly unpopular with the ladies. But what does Polaris have to do with their fate? And will they ever get that harem they've always wanted?