It began when Tukhachevsky (in the Benad361 parody: "They came from Planet F") performed a hilarious antic on Hitler (see Antic-Aliens) and Fegelein (despite denying it) got the credit.
Tukhachevsky was furious, and tried to unleash several antics on Fegelein to kill him in the parody: Tukhachevsky versus Fegelein: Round One (which ultimately failed).
Fegelein retaliated in Tukhachevsky versus Fegelein: Round Two by hacking Tukhachevsky's email using a "antic hacking kit" purchased from antic dealer Albert Speer, which he uses to bypass the antic-defences and access Tukhachevsky's passwords. He then anonymously sends copies of emails in which Tukhachevsky has been rude about Stalin, to secret police chief and informer Yezhov, who reads them to Stalin. Stalin is surprisingly calm, to the extent that Tukhachevsky is not shot. However, he gives Yezhov free-reign to punish Tukhachevsky and orders him to "Be savage." Yezhov arrests Tukhachevsky and unleashes his "castration skills" which put the marshal in horrendous pain, though they do not kill him.
In Tukhachevsky versus Fegelein: Round Three Tukhachevsky strikes back with a successful antic. He frames Fegelein in an antic in which a speech by Helmuth Weidling to the inhabitants of Berlin (while Hitler is away) is tampered with (laced with Soviet propaganda and insults). Nobody believes Fegelein's denials and he is executed for "spreading propaganda via antics".
In Round 4, Stalin sends Tukhachevsky on a very important assignment to steal a German Wunderwaffe from the Eastern front, to help their Antic War effort. He steals several hovercraft, but Fegelein stops Tukhachevsky in a long hovercraft chase/fight which ends up in Tukhachevsky and the last remaining hovercraft being hurled off a waterfall (Anticagara falls). Tukhachevsky is then shot and wounded by Stalin upon his return, as punishment for his failure.
In Round 5 (the final episode) Tukhachevsky worries about the prospect of war with Antonescu Parodies and invites Stalin, Lt Werner (from U-Boat Parodies), Romanian president Nicolae Ceausescu (from Ceausescu Parodies), Libyan leader Muammar Gaddafi (from Gaddafi Parodies) and German Fuhrer Adolf Hitler to a conference on his Antic Jet, to discuss the chance of a united front in the face of any kind of war, and an end to the ongoing antic war/s.
However, Fegelein tells Himmler that he is enraged at not being invited. He sneaks onto the plane (hiding in the cargo hold) planning to attack Tukhachevsky in revenge. After the group have been on the flight for some time (and had some typical fights and confrontations) they confer and agree to go to the glass-windowed viewing deck to sign the treaty, and so Tukhachevsky can show them his new "Antic Armour he built". Fegelein emerges and tries to shoot Tukhachevsky. However Hitler grabs him at the last moment, messing up his aim and causing a bullet from his gun to shoot a hole in a window instead. The glass breaks and the air pressure collapses. Werner is instantly sucked out of the broken window, followed by Hitler and all the other dictators (Stalin manages to hold onto a chair and is one of the last to be sucked out into the atmosphere). This is made worse as the collapse of the air pressure causes the plane to go into a steep dive.Fegelein then confronts Tukhachevsky, fighting hand-to-hand as the plane starts to break up and crash due to climbing too high into the atmosphere. Fegelein scores several hits on Tukhachevsky and looks set for a potential victory. However Tukhachevsky activates the self-defence mechanism in his antic armour and electrocutes Fegelein with "1,000,000 Antic Watts a minute". He then brings him down with a punch.
Shortly thereafter the plane crashes and all remaining passengers are dead by this point. What exactly happened to the two is unknown. However a possible scenario is shown in which Fegelein is still lying on the ground in shock, while Tukhachevsky dons a parachute (throwing the spare out of the broken window) and plans to escape. He begins a monologue, taunting Fegelein about how his "Nazi antic bullshit" was doomed to fail. Fegelein springs to life and pulls the parachute cord, dragging Tukhachevsky out of the plane where he clings on to the edge for dear life. Fegelein then comes up to him, declaring that they will both die and nobody won the war, but he will still send Tukhachevsky to "Antic Hell" first. He activates the self-defence mechanism on Tukhachevsky's armour, electrocuting him (as he was holding onto metal) and causing him to lose his grip. He is dragged into the engine by the parachute and cut to pieces. Fegelein is then killed in the plane crash.
Benad361 revealed at the ending that this does not mean that these characters have departed his parodies indefinitely. He also hinted that the various dictators and representatives at the conference who fell out of the window may have survived the fall. There was some speculation in the comments of the video regarding possible outcomes, which included the theories that Hitler landed in John Mallory's house and had to return to Berlin looking half-blown up, Felicity Merriman rescued Lt. Werner when she flew past in a biplane, Stalin landed in a vat of antic potion that made him look like a Nazi general and was subsequently beaten up when he arrived at the Kremlin, and Gaddafi landed in the middle of a group of protestors.
On the 20th July 2012, Benad361 released a previously unreleased parody entitled Tukhachevsky versus Fegelein: Arctic Annihilation (which he had thought was lost on his old laptop when it finally broke down) showing an alternative ending to the conflict (that is, if none of the events in the final episode had happened) in which Tukhachevsky is assigned a mission by Stalin to track down Fegelein in his Arctic base, find out his secrets and eliminate him.
Tukhachevsky does so, promising Stalin a victory. However, he is just about to ambush Fegelein in his Aston Martin Vanquish: Antic Class when one of Fegelein's guards on a snowspeeder crashes into the invisible car (made invisible via antic technology) and flips through mid-air - right in front of Fegelein. He detects the presence of Tukhachevsky and alerts his guards. He himself commandeers his personal Jaguar XKF (Fegel) which Speer and Himmler designed for him, and the two engage in a long-running fight over the ice in their cars, which are modified to utilise a great range of antic-related weapons such as Antic-Missiles, machine guns, mortars, and so on.
Fegelein tries to destroy his ice-base with his Fegel-ray. However, Tukhachevsky flees inside the melting base (knocking Himmler and Gaddafi aside with his car when they try to assist Fegelein on snowspeeders) and Fegelein follows him, fighting their way all the way up to the top of the melting base. It looks like Fegelein has Tukhachevsky cornered, but Tukhachevsky's Aston Martin's adaptive camouflage ability (which renders the car invisible) has restored itself by this point (after previously being damaged in the battle). Tukhachevsky activates this just as Fegelein's car deploys a battering ram and charges at Tukhachevsky's. Fegelein loses his focus as Tukhachevsky's car turns invisible and moves in the nick of time, meaning that he and his car plummet off the balcony and into the icy water below.
Fegelein's car is lost, but Fegelein rises to the surface and starts to bitterly lament the loss of his car (saying that he had "five more payments" to make on it). As he does so, Tukhachevsky fires several shots from his Antic Pistol out of his car window and breaks the cable holding the diamond chandelier on the ceiling above Fegelein, which falls and impales him head-first, killing him. Tukhachevsky then escapes the building. We then hear Fegelein say "I used to be an Antic Master, then I took a chandelier to the face".
All these antics and counter-antics were a notable part of the ongoing Nazi-Soviet Antic War (a theme of Benad361 parodies) between Germany and Russia, as a result of Tukhachevsky's antics against Hitler(see the Benad361 parody: "Tukhavchevsky's First Antic"). The final episode (released on the 15th May) was a wide-ranging episode which included characters from U-Boat Parodies, Ceausescu Parodies, Gaddafi Parodies, Downfall Parodies (as per norm) and Stalin Parodies (as per norm). The parody series is lengthy (one part being over ten minutes long) and involved much use of FX via Sony Vegas.
The two have presumably been resurrected by the power of antics since their demise. However, it is unknown if they have become friends or remain enemies.