The Academy's Weapon Replicator

Etius is a game that no one has ever cleared, and when every strategy fails, its player wakes up inside the game as Frondier, an extra character. A main quest warns him that humanity faces destruction and tasks him with changing its fate. Frondier’s only ability is Weaving, a skill that saves and replicates objects as virtual illusions. With this power, he must copy whatever he can and use those duplicates to overcome the odds and forge a new destiny.