The Aeshi Nero is a gigantic excavator resembling a cobra. Designed to travel through the underground,it is used by the rebels. Although it's primarily designed for digging tunnels, it can be re-purposed for combat in a pinch.
Although Metal Slug 2 implies that it's a Martian machine (Martian-affiliate music plays during the fight instead of the standard boss music, and only supernatural enemies appear throughout the level - it's likely a reference to "alien hunters" who believe the Pyramids were built by aliens), its description in Metal Slug Attack confirms that it was constructed by the Rebels to clear out room for a base.
You fight this boss in a tower inside a tomb, with it digging through and suddenly appearing from the bottom. Whenever you climb, it will also follow you, while launching missiles and electric balls. It will also intermittently charge and fire its laser cannon that will go up the entire tower, ｂthe laser are extremely fast, forcing you to go to the edge of a wooden platform to avoid it. The missiles and electrics are easy to dodge, but the fact that you are in a limited space and can fall to your death if you weren't careful tends to make this boss a bit hard. Also, it may suddenly crawl up and electrocute you with energy sparks, so keep on jumping up. Having Slugnoid will make the battle much shorter. However, losing the slug can make this fight quite annoying, as you have to constantly jump and shoot down. Sometimes a Rocket Launcher or a heavy MG box will drop down, however they may fall on inside this boss's mouth, making the retrieval process difficult.
- It appears in Metal Slug Attack as a boss, in the new stage in Extra Ops. Also it is a playable unit and one of the most difficult units to obtain.
- If you move yourself to the lower right platform below the last item on the tower with the right timing, Aeshi Nero will stop at the base of the tower and not damage you, making it possible to defeat without climbing the tower (by using the Slug to continuously fire downwards without jumping) or taking on its attacks. This glitch only works in Metal Slug 2, in the revamped Metal Slug X, jumping on that platform will result in the eventual destruction of the humanoid Slug (it is still possible to jump out of the slug or out of the Aeshi Nero's mouth).