Achilles was first hinted at in episode 2 of Danball Senki. During the Tiny Orbit board meeting, Yūsuke Uzaki revealed the data and schematics for the cutting edge LBX, marked to be more advanced than models that previously came before. The only information they've obtained about the creator was that the creator's name was J.
The only model was sent to Kitijama's Model Shop presumably met for Ban Yamano. However, on order from Ren Hiyama, Hanzou Gouda tricked one of the owners, Saki Kitijama into selling him the armor frame. After defeating the Devas, Ban and his friends reach Hanzou's hideout.
In the next episode, Hanzou gives Ban the frame. He attaches the frames and armaments onto AX-00 to officially complete Achilles. However, to keep the armor, Achilles must win against Hakai-O and his friends' LBX are allowed to assist him. Thankfully, Achilles proved to be skilled in attack, defense, and speed. It was easily able to outmaneuver Hakai-O. After Ban's determination to win helped him master his new LBX, Achilles was capable of blocking Hakai-O's heavy sword with it's shield and striking a kick to knock the behemoth down. After the plan between Kunoichi to destroy the chest part, Achilles and Hakai-O engage in a finishing lunging strike, with it as the victor.
How to Unlock
Scan Achilles' AR Icon from the M.U.G.E.N Trilogy website.