The Superhuman Gambit

The Superhuman Gambit is a Fallout 3 side quest. It is also a Xbox 360/PC achievement and PlayStation 3 trophy.

Detailed walkthrough
The town of Canterbury Commons has become the battleground of a "super-villain" - the AntAgonizer and a "super-hero" - the Mechanist. Its inhabitants are not very happy about it (save for Derek Pacion) and ask you if you can help them.

Upon arriving in Canterbury Commons, the AntAgonizer and the Mechanist will be engaged in a standoff. After a few scripted opening semantics, the two will engage in a brawl. Once the dust clears, both will run away, and Uncle Roe will speak to you, asking you to handle the ordeal. With a speech check, you can double the pay, from 200 to 400 caps. After you have accepted the quest, speak to Derek Pacion. He gives you the best info on where to find them. The AntAgonizer lives in a cave north of town and the Mechanist lives south of town in an old robot factory. (Both locations will be marked on your map.) With the Child at Heart perk, you can ask Derek for their weaknesses. The Mechanist does not harm the innocent, and other than the royal guard, the AntAgonizer's ants are weak. He will also comment that you should become a superhero named "Awesome-Claw", and suggest you lead an army of deathclaws against them. He may alternatively tell you that you should be called "Super Humongous" and command a group of super mutants to do your bidding. He may also call you "Shadow Bite," or the "Brilliant Shadow," commanding an army of mole rats. There are several other names he may suggest, such as "The Lucky Guy" depending on high skills or S.P.E.C.I.A.L. stats.

AntAgonizer's Lair
If you decide to take out the AntAgonizer, you need to head to the AntAgonizer's lair north of town. Go down all three sets of stairs and enter the first room to the right after the bend in the hallway. A button on the wall opposite of the entryway lowers a staircase to a cave. Continue through the cave to the AntAgonizer's lair.

Alternatively, you can sneak in the back entrance - a pipe to the west of the entrance at the top of the same mountain of rocks that the main entrance is on (requires a lockpick skill of 50). This route bypasses all of the ants in the tunnels. It is also possible to use this entrance if you pickpocketed the AntAgonizer's key during the brawl when first entering town.

Once in her lair, there are no ants to fight, just the AntAgonizer. There are several ways to interact with her at this point:
 * If you have already received the Mechanist's costume and are wearing it, after a brief introduction she will attack the player along with her ants, believing you to be the Mechanist.
 * If you have the Mechanist's costume, but are not wearing it, you have the option of giving it to her. You will be awarded with the Ant's Sting, a knife that poisons an enemy for an additional 4 damage per second for 10 seconds, and negative Karma (as she remains a delusional "super villain").
 * By attacking her or speaking with her and being aggressive, you can engage her in battle. Killing the AntAgonizer will not affect your Karma even though she is an evil character.
 * Speaking with her, you can choose to help her destroy the Mechanist. The Mechanist will barge into her lair and you will have to fight him.
 * If you choose to tell her the suit is not worth her attention, she will agree with that, and then prepare to leave the town. Though it may seem a good deed, you will still receive negative karma for choosing this option.
 * You must pass a speech test and have her real name given to you by Joe Porter to convince her to see the error of her ways. Having the Lady Killer perk guarantees success. She will then give up her career as a super villain, hand you her costume and leave quietly.
 * If the Lone Wanderer has been to Hubris Comics and read the note to the editor about AntAgonizer's canceled Grognak the Barbarian comic, they can use this to point out that she can still be redeemed. Doing so will yield good Karma. This bypasses the gender-specific perk and means they do not need to make the very tough speech check and will also receive her costume.

Mechanist's Forge
The Mechanist's Forge is located just south of town on higher ground, inside the Robot Repair Center.

To reach his hideout without having to fight through his robotic security, you can lockpick the elevator in the hallway across from the entrance, bypassing the heavily guarded stairs. This requires a skill of 75 or above. Otherwise, the facility is broken up into four sections: Office (left of the entrance), two Maintenance areas (Sector A and B, which are connected by a control room on the upper level) and the Mechanist's Forge which allows entrance to the Mechanist's lair via the coffee maker. Sector B is closest to the entrance (metal door past the elevator), and the Forge entrance is on the upper level of Sector A, where activation of the coffee maker accesses the hideout. If accessing via the elevator, you will not need to activate the coffee maker, as it is on the other side of the corrugated door seen in the Mechanist's lair. This can be confusing as the entrance from the elevator, and the entrance from the upper level are both called Mechanist's Forge.

The security terminal for Sector B is in the control room on the upper level, which allows you to disable the automatic turrets and security robots. The security terminal for Sector A is located in a small control room near the back of the bay, close to the Forge entrance (upper level). From this terminal, you can disable the automatic turrets in this room, as well as emit an emergency pulse explosion that will destroy any active robots in this sector.

If you killed the AntAngonizer earlier, then you will need a lock pick skill of 75 to open the Mechanist's lair.

Once you enter the forge, activate the coffee maker to reveal the Mechanist's lair. You then need to activate one of the little gears to the right of the door.

Once in the Mechanist's lair you have several options that echo the interactions with the AntAgonizer:
 * If you are wearing the AntAgonizer's costume, he will believe you to be her and attack you.
 * If you are not wearing the AntAgonizer's costume, but have it in your possession, you may give the costume to the Mechanist. The Mechanist will give you Protectron's Gaze, a laser pistol that fires bursts of laser fire like a shotgun, and you will receive negative Karma (as he remains a delusional "superhero"). It can not be obtained by killing him; his body only holds a normal laser pistol when looted.
 * Attacking the Mechanist or using threatening speech, will of course result in the Mechanist turning hostile and fighting you. Killing the Mechanist does not result in negative Karma.
 * If you choose to help him defeat the AntAgonizer he will say something about her attacking the forge. You will then have to follow the Mechanist and help him defeat her and her ants.
 * Convincing the Mechanist to end his superhero career and leave the town alone will grant you his suit and positive Karma (like with the AntAgonizer, it is a very difficult speech check).
 * Either the Black Widow or the Child at Heart perks give a dialogue option to tell him he is scaring the whole town. With that, he will give you his suit and leave (If you have both perks, only the Black Widow dialogue choice will be available). This also results in positive Karma while allowing you to bypass the speech check.

Reward
OR OR
 * 200 caps (Stopping one of them)
 * 400 caps (Stopping both, or asking with the Speech skill to be paid 400 and stop one)
 * 600 caps (Stopping both after asking for 400 caps with the Speech skill)

Bugs

 * If you walk into Canterbury Commons from the north and enter Dominic and Machete's house first, you will not see the fight between the AntAgonizer and the Mechanist, yet Roe and everyone in town will act as if you did.
 * If you do not stay to watch the event between the AntAgonizer and the Mechanist, and then immediately speak to Uncle Roe, all three characters may disappear. If this occurs, the quest cannot be finished.
 * When you first come to Canterbury Commons and you see the Mechanist and the AntAngonizer fighting, when you target the ants, they will have no name and be blank.
 * The AntAgonizer's health sometimes will not decrease despite being hit numerous times - this occurs even in her lair. The only known fix is to continue hitting her until she randomly dies.
 * Reverse-pickpocketing a suit from either the Mechanist or AntAgonizer and giving it to the opposing party will update your quest status to "Report back to town for your reward" (as should normally happen). However, speaking to Uncle Roe will not reveal the normal dialogue choice to end the quest and receive your reward. This can be circumvented by killing either the Mechanist or the AntAgonizer, or both.
 * When you team up with the Mechanist and have to defend the Forge, he may wander off and disappear. When you talk to Uncle Roe after killing the AntAgonizer, it shows you that the Mechanist has died; therefore you are unable to receive the Protectron's Gaze.
 * After you convince the AntAgonizer to leave, she will travel to Megaton. If you have blown up Megaton before this quest, she will enter through a door inaccessible to the player, meaning that the optional objective to kill her is impossible to complete.
 * Sometimes the Mechanist's sentry bot will stay in the same position for the rest of the game; it can be handy as it makes a very efficient guard for the town.
 * If you passed the speech check with The Mechanist and you turned off the turrets in sector A instead of destroying them they will become hostile towards The Mechanist and kill him. If you reach the terminal before/after they kill him, it will show the turrets as still being disabled.
 * Very rarely, when you fast travel to Canterbury Commons after completing a quest, especially at a high level, a random enemy will spawn at the diner in-front of where you spawn. If you are a higher level, it could be a deathclaw or even an albino radscorpion. If this happens, usually it will kill almost everyone and then head for you. Just reload the game from the autosave and it will not be there the next time you fast travel.
 * Upon entering the Mechanist's forge after completing the quest, he will not appear where he should.
 * If either of the two robots the Mechanist controls in the encounter the player witnesses on arrival is killed, they may be replaced randomly at a later date by two functional robots, possibly different types. These new robots will be friendly to both the player and the town, and will attack enemies to either. They will remain at the entrance to the town.
 * If you manage to somehow obtain both the ant's sting and the Protectron's Gaze before you speak to Derek Pacion, the only way to finish the quest is to kill either the AntAgonizer or the Mechanist, then speak to Uncle Roe. you can not obtain the 600 caps because of this.

Der übermenschliche Gambit El gambito superhumano Нечеловеческий гамбит