Mazinger Z vs The Great Dark General

Nobita and Doraemon find a giant robot in pieces which they later assemble. It turns out to be a destructive weapon and the gang must save Earth from an imminent invasion.

After discovering the face of their true enemy, someone who is related to Akito and responsible for the Geass placed upon him, W-0 attempts to return to their base at Castle Weisswolf. However, stranded in Warsaw due to a complication involving their military identification, they are forced to accept the help of local gypsies, allowing the squad to take some time to deepen their bonds. Meanwhile, Britannian advisor Julius Kingsley and his guard Suzaku Kururugi begin working together with the Knights of St. Michael in order to crush the European resistance once and for all, armed with the destructive power of a giant weapon known as the Ark Fleet.

The Ark Fleet has been destroyed, and a significant number of the enemy's troops have been wiped out due to its crash landing. As the remaining forces of the Holy Order of Michael regroup in order to launch a final assault on Weiswolf Castle, the wZERO unit, along with their new ally Ashley Ashra, stand ready to intercept them. Meanwhile, with his Geass out of control, Shin moves to erase his younger brother's existence once and for all. But Akito, having promised Leila that he will come back alive, refuses to accept such a fate, and the two clash in their final battle.

In a society devastated by the effects of an all-out war between heroes and villains, a mysterious giant fortress suddenly appears, engulfing towns and people one after another. Then, a man reminiscent of All Might, the 'symbol of peace', stands in front of Izuku and his friends...