Allen O'Neil/Appearances

Allen O'Neil
Known as "The Immortal Devil Sergeant" of the Rebel Army. He's the most powerful of all soldiers in battle. He usually attack you from the ground, but also can attack you from the air. Equipped with a M60 Heavy Machine Gun, grenades and a knife, he can be a real nightmare.

Other Appearances
There are also some other characters based on O'Neil:

Allen O'Neil Jr
See list this: Allen O'Neil Junior

The son that follows the example of his father in Metal Slug Advance.

Mecha Allen
An android impersonator of O'Neil. Only in Metal Slug 4.

Evil Allen
An demon impersonator of O'Neil. Only feature in Metal Slug: New Chronicle Arrangement.

Infected Allen
An zombie impersonator of O'Neil. Only feature in Metal Slug: New Chronicle Arrangement.