I Was Supposed to Retire, So Why Am I Saving the World Again?

[A powerful duo, with the heroine even stronger + military academy + ensemble cast + world contamination] After completing upgrade missions across countless worlds, Mu Zi happily retired! Just as she was preparing to return to her hometown, Blue Star, to enjoy her retirement, the System sent her to Blue Star a century later, where dream beasts ran rampant! Mu Zi: System, care to explain? System: Host, just tell me, is this Blue Star or not? Now she has two choices: One, start leveling up again, kill every dream beast, and reach the pinnacle of Blue Star! Two, find someone with a dream ability that can reverse time and return to the peaceful Blue Star of a century ago. Okay, she's an expert at leveling up again. But can someone tell her why her psychic power, which is above level five, only summoned a tiny key with no offensive power at all? Luo Yinzhen, the head of District Ten, looked down at the new faces below. "I hope all prospective students work hard to improve their psychic powers and abilities. I look forward to seeing you at the military academy and in the military district." A year later, Mu Zi held a giant cannon in her left hand and swung an enormous key in her right. "Who else wants some?!"