I don't really own Mega Man, DC, Marvel and/or Transformers. Mega Man still owns by Capcom, DC and Marvel owns by themselves (that I know or think), Transformers owns by Hasbro Studios.
My version of this Mega Man title belongs to Capcom, DC, Marvel, Orion Pictures and Hasbro Studios, because of Autobots and Decepticons. This version is partially inspired by the Super Adventure Rockman, but instead of Ra Moon and Ra Devil, the title shows Decepticons such as Megatronus and Barricade. ED-209s are from RoboCop, which owns by Orion Pictures.
Characters on Mega Man's side:
Nick Fury, Mega Man, Eddie, Rush, Darci Roll, Supergirl, Black Panther, Wolverine, Storm, Shadowcat, Rogue, Professor X, Ice Guy, Phoenix/Jean Grey, Beast, Cyclops, Angel, Nightcrawler, Mr. Fantastic, Invisible Woman, Harley Quinn, Deadpool, Cat Woman, The Thing, Human Torch, Spider-Man, Iron Man, War Machine, The Penguin, Cyborg, Captain America, Batman, Black Canary, Robin, Black Widow and Hawkeye, plus Autobots such as Optimus Prime, Bumblebee, Sentinel Prime, Prima, Alpha Trion, Vector Prime, Quintus Prime, Nexus Prime, Solus Prime, Liege Maximo, Alchemist Prime, Amalgamous Prime, Onyx Prime and Micronus Prime, Proto Man (first from the end, when he changes his side and turns against Wily)
Neutral for now:
Lex Luthor and Mercy Graves
Characters on Wily's side:
Dr Wily, Proto Man (until the end), Callisto, Pyro, Magneto, Lady Deathstrike, Dr. Doom, Electro, Green Goblin, Dr. Octopus, Bane, three of ED-209s and two of Rolling Drills, Dive Man, Drill Man, Toad Man, Bright Man, Pharaoh Man, Ring Man, Dust Man, Skull Man, Twin Robots, Stone Man, Charge Man, Wave Man, Star Man, Gravity Man, Gyro Man, Crystal Man, Napalm Man, Dark Man 1, Dark Man 2, Dark Man 3, Dark Man 4, Magnet Man, Hard Man, Top Man, Snake Man, Shadow Man, Spark Man, Gemini Man, Needle Man, Mecha Dragon, Metal Man, Air Man, Heat Man, Flash Man, Bubble Man, Wood Man, Crash Man, Quick Man, Water Man, Volt Man, Dyna Man, Titanium Man, Guts Man, Cut Man, Elec Man, Ice Man, Fire Man, Bomb Man, Bass?, Treble, plus Decepticon robots such as Barricade and Megatronus Prime/The Fallen
Mega Man 5: Birth of First Transformers (earliest 12th Sep 2067) (Over a year after Wily's defeat from the previous event)
It has been at least six months ago since the first Transformers robots are already born, Optimus Prime, Sentinel Prime, Prima, Alpha Trion, Vector Prime, Quintus Prime, Nexus Prime, Solus Prime, Liege Maximo, Alchemist Prime, Amalgamous Prime, Onyx Prime, Micronus Prime and even Megatronus Prime. These robots are created by both the team of "Justice of Superhumans" and "LexCorp". However, Megatronus went aggressive and went to wrong hands, where Wily was, with help of supervillains and of course Proto Man, controls that Robot, who became a Prime of Decepticon. There were also other Decepticons from the past, but they were only robot masters, mini- and other robo-bosses, plus of course Proto Man.
Now, Barricade is recently born as a new Decepticon robot, while Bumblebee from the heroes side born as a new Autobot. After that Dr Wily with help of two Decepticon robots, revives robot masters from Mega Man 1-5, plus some of Mini-bosses of ED-209s and Rolling Drills, and of course Mecha Dragon, Twin Robots, Dark Man 1, Dark Man 2, Dark Man 3 and Dark Man 4.
Now, Dr Wily is in a special place, located somewhere in the World. Mega Man along with his old friends (superhuman heroes) and new ones (Autobots) are coming to this special place, where Wily is. Those heroes along with Autobots reaches to the place within hours, probably by flight.
Wily is quite mad. For the first time, he won't only name his robots for Wily's, but also rename (even those robots which aren't originally from Transformers) them as Decepticons along with those aggressive Transformers robots.
Mega Man along with his hero and Autobot friends separates to find a way to see and explore what Wily and those Decepticon robots (including ED 209s from RoboCop, other robots from original Mega Man and Transformers-series). There are at least three Rolling Drills and two ED-209s, totally five of all mini-boss robots. So Mega Man and his hero friend will separate into two different groups, to first defeat those mini-bosses and robot masters. But first of all Iron Man and War Machine together must see threats under water, so they are diving.
When those heroes are diving underwater to find a threat. Then Water Man surprisingly comes out to threaten them. Iron Man and War Machine says to him "Do you know, about what you're doing?".
Water Man (in DOS-version called for "Sonic Man") responds "Yes, but I won't allow you to pass through me".
"Okay, so It'll be a trouble" as Iron Man says. Iron Man and War Machine quickly defeats Water Man, with to destroy this robot.
After defeating Water Man, Iron Man and War Machine passes on through the water, then they meets Bubble Man.
War Machine asks Bubble Man "Do you know about Wily's plans?".
Bubble Man responds "Yes, but I won't allow you to know the truth".
War Machine answers back "Okay, so we'll have to make a trouble".
War Machine and Iron Man together defeats Bubble Man.
After defeating Bubble Man, Iron Man and War Machine passes on through the water, then they meets Wave Man.
"Do you know about what you're searching for?" as Iron Man asks Wave Man for.
"Yes, I do. But I won't allow you to know about it." as Wave Man answers back.
"Okay, we'll have to stop you" as Iron Man responds.
Iron Man and War Machine quickly defeats Wave Man. Only briefly after defeating Wave Man, they meets Dive Man.
"What is your plan?" as War Machine asks Dive Man for.
"I'm asking you for the same thing, but forget to have an answer, or you're not allowed to pass further through me" as Dive Man answering him back.
"So, it is time for an action" War Machine says.
Now, War Machine and Iron Man together quickly defeats Dive Man. War Machine and Iron Man finds a symbol which is the key to defeat Wily. Iron Man and War Machine comes back to Mega Man and his hero league, with even Autobots. Autobots will see what those heroes (including Mega Man) are doing. Those heroes separates into two different groups;
Group 1: Nick Fury, Mega Man, Eddie, Rush, Darci Roll, Super Girl, War Machine, Captain America, Bat Man, The Penguin, Ice Guy, Spider-Man, Beast, Harley Quinn, Deadpool, Hawkeye and Cat Woman,
and
Group 2: Black Panther, Wolverine, Storm, Shadowcat, Rogue, Professor X, Phoenix/Jean Grey, Cyclops, Nightcrawler, Mr. Fantastic, Invisible Woman, The Thing, Angel, Human Torch, Iron Man, Cyborg, Black Canary, Robin and Black Widow.
Group 1 chooses the left path, while Group 2 chooses the right path.
After both of those groups choosed their paths, the first group meets Cut Man with Sniper Joes, Mets and even some Robo-animals.
"Hey Cut Man, drop your weapons down" as Mega Man says to him.
"Never, I'm not dropping my weapons off, go home" as Cut Man responds.
"Okay, we'll make a trouble" as Mega Man responds.
Mega Man and Spider-Man confronts Cut Man, while the other members of Group 1 confronts other robots. When Mega Man and Spider-Man together defeats Cut Man, the other robots surrenders.
Briefly after defeating Cut Man, Group 1 meets Fire Man with Mets and Sniper Joes, Group 2 meets Ice Man with Sniper Joes. Batman defeats Fire Man, while Cyclops and Invisible Woman defeats Ice Man. After defeating those robot masters those Sniper Joes and Metbots surrenders.
After Group 1 and 2 defeated Fire Man respectively Ice Man, Group 1 meets Bomb Man with only four Sniper Joes and three Metbots. This makes War Machine and Supergirl together quickly win over Bomb Man.
Briefly after defeating Bomb Man, Group 1 meets Elec Man.
"Hello Elec Man, can you please tell us about what's going on?" as Captain America asks him about.
"I'm sorry, I'll say no" as Elec Man says.
"Okay, we'll make a trouble" as Captain America says.
During the conflict between the group and Elec Man, only Mega Man and Cyborg hides themselves. When one of them is behind Elec Man, the robot master would be hitten by Mega Buster. Both Mega Man and Cyborg hidden forces Elec Man to surrender.
After defeating Elec Man, Group 1 meets Guts Man. The robot master have an army of Sniper Joes and Metbots.
"There's no way to escape, go back to your home or die" as Guts Man tries to warn the group about.
"Okay, but we'll resist your attack" as the group responds.
However, the group defeats both the army and their robot master, Guts Man. After being defeated, Guts Man and the other robots surrenders.
After Group 1 defeated Guts Man, the Group 2 meets Titanium Man.
However, Group 2 together defeats Titanium Man.
After Group 2 defeated Titanium Man, this group meets Dyna Man, while Group 1 meets Volt Man.
Group 1 defeats Volt Man, while Group 2 defeats Dyna Man.
After Group 1 and 2 defeated Volt Man respectively Dyna Man. Group 1 meets Metal Man with his army of Sniper Joes and Metbots.
"Can you tell us about what is going on here?" as Mega Man asks Metal Man.
"Sorry, I won't, go back to your home" as Metal Man answers back.
"Ok, we'll make a trouble" as Mega Man responds back.
During the conflict, Mega Man quickly defeats Metal Man. Then the group forces the robot master, plus those Sniper Joes and Metbots to resign.
After defeating Metal Man, Group 1 meets Heat Man with an army of Sniper Joes and Metbots, while Group 2 meets Flash Man with an army of Metbots. However, Ice Guy confronts and defeats Heat Man, while the other members of the group confronts other hostile robots. Cyborg, Cyclops and Invisible Woman defeats Flash Man, while the other members of Group 2 confronts other robots. After defeating Heat Man and Flash Man, the other robots surrenders.
Later, Group 1 meets Quick Man with an army of Sniper Joes and Metbots.
"Will you tell us about what's going on?" as Captain America asks Quick Man for.
"I won't reveal, go back to your home! Or I have to attack you" as Quick Man responds.
"Okay, it's action time!" as Captain America shouts.
Captain America confronts Quick Man, while the other confronts, and stops the other robots. In last Captain America defeats Quick Man, which forces the other robots to surrender.
Briefly after defeating Quick Man, this Group meets Wood Man with an army of Sniper Joes and Metbots. However, Hawkeye and Super Girl defeats Wood Man, while the rest of the members forces other hostile robots to surrender.
After defeating Wood Man, they continues on to the next place...
To be continued...