The unnamed Professor is a new character introduced in Metal Slug Attack and one of the prominent characters of that game.
A former scientist for the Rebel Army, he at some point joined the Martians after taking an interest in their technology. Joining the Martians, he learned how to create clones, mutate beings and used his knowledge during his time with the Rebels to create robots based from the aliens' designs, such as his modified Ring Laser Mecha and the Mars Brain Robot. He also learned how to communicate with the Mars People.
He seems to be impressed with Marco Rossi due to his ability to create "life" (Marco created MS-Alice, an AI). He is also interested in Eri Kasamoto, as while examining her memories, he was impressed with the military experiences she had and planned to use it for future purposes.
With the release of Navy, another Rebel scientist, it is implied with her infobox that she did not get along with him while he was the chief. During his time in the Rebel Army, he also had an assistant named Percier, who called him her "eternal servant", though he abandoned her when he defected to the Martians. He eventually took her back in during a raid to save Marty.
After heard that the Rebel Army got more support from Future Rebels, he got interested in their new technology. He surprised the Future Rebels and killed all of the infantry. The remaining rebels sent the Kraken after him, and after a decisive battle, defeats it. He takes the remains of the Kraken with him to study the technology of the future.
The Professor later appears again in the Extra Ops "Signal Red", where he is seen inside the Rugname trying to extract a special Brain Robot, accompanied by a red Ring Laser Mecha. Morden sends Vita to stop him. When Vita arrives, she battles the Mars Brain Robot and destroys it. The Professor then tries to kill Vita, but she dodges his attack and knocks him unconscious. He is saved when the red Ring Laser Mecha arrives, as Vita leaves after a brief confrontation.
Sometime after those events, in "Mad Scientists", the Professor builds himself a new Mars Mecha and attempts to learn more about Vita with the help of two Martians; Marty and a disguised Martian. He confronts Navy, though he is easily defeated by her. Before Navy can do anything, the two Martians appear to distract her and teleport away with him in tow.
In order to combat Vita, the Professor made a clone of Abigail (named Clone Abby), making it the same as her, though he made it emotionless to ensure absolute loyalty and completing tasks without question. It is presumed that he was aware of her crush on Trevor and not aware of the stronger Nova. He sent Clone Abby out on a test run, attacking a Rebel engineering facility where the new Emain Macha twins were being constructed. It severely damaged the Drache Macha, which he was pleased with and told Abigail that he would improve on Clone Abby with the results it collected before having it depart.
Instead, he simply created a clone of Beatriz (named Clone Betty).
The Professor captures Marco, Eri and Tarma in order to study their minds. He's impressed with Marco and Eri, but is disappointed with Tarma. He also captured several Regular Army soldiers for experimentation, and after being defeated, Marty arrives and informs him to enter the Rugname.
His reasons for joining the Martians are detailed in "Utopia", where he was amazed by their technology. After passing several tests, Rootmars allows him to join, and he begins to give the Martians names as he is annoyed that they don't have any.
When Marty is abducted by the Rebel Army, he goes out to search for him with two Cadres. During the mission, he finds Percier and has her tag along, not wanting to leave her by herself. Apart from that, the events almost mirrors the Extra Ops "Black Future".
In "Cross/You", the Professor had a discussion with Navy regarding Vita. The Professor felt that it was best to suppress Vita's memories, as he stated several flaws that it had by not adding a personality modifier. Navy refused to do so, believing life in a different meaning. The Professor told her that she had one month to do it, or he would do it himself. However, this never happened, as he defected to the Martians during this time frame.
- The Professor's mech is a Ring Laser Mecha / Mini-UFO combination, using a Vanguard's arms.
- After winning or while using his special, the Professor laughs in a similar way to most Rebel Army units.
- When placed in the same Metal Slug Attack deck, he and El Dorado form the "New Face II" team. This lowers their AP cost for sorties by 10%.
- The Professor himself appears to be a reference to Dr. Emmett Brown. The two share a similar appearance, and the logo for the Extra Ops event he first appeared in, "Black Future", bears more than a passing resemblance to those used for the "Back to the Future" movie series. This is further supported with his assistant Marty, who shares the exact name and role as in Back to the Future.
- His mecha's control panel matches that of a NeoGeo arcade cabinet.
- He is available for purchase at the United Shop in the 4th United Front event.