When I first heard about this contest the only thing I could think of for an unstoppable force was a disease or some big corporation. It took me a while, but I really like the idea of the Flood from the Halo franchise.
The Flood was first introduced in to the world in 2001 in Halo: Combat Evolved where they were a third faction within the game. The Flood acts like a disease or some crazy virus that is crazed to infect any life form they encounter. This life form can be dead or alive, it doesn't matter to the Flood! Once they find a life form they control that body and animate it to its own desires. The ancient Forerunners in Halo were so terrified of this new menace that they committed suicide and ended sentient life nearly 100,00 years before Master Chief trying to starve the Flood to death.
These guys spread like wild fire! I remember the first time I saw these exploding through the door I just started spraying bullets while I was on the edge of my seat!
So who could stop the flood? Master Chief wasn't able to, he luckily was able to escape from these guys!
I turn to other main characters in video games and ponder who would be able to stop this menace? These characters could only be in video games, so no Jedi or any movie characters will work here. They would also need to be a Playable character. With this in mind I came up with 4 characters that could destroy the flood for good!
WHA?!?! A girl on this list? She is no ordinary girl! she is a super powerful 500+ year old witch that has a huge Arsenal to back her up. Not only does she fight hordes of Angels on a day to day basis, but she has the power to summon huge monsters and even body parts to help her fight. She wields four weapons, from pistols to bazookas, on her legs or in her hands. She also wields the power to slow down time to move a ridiculous speeds. If she is not able to take down the Flood single handily then she can have back up from this guy!
Death is from the Darksiders games and he is actually one of the 4 hoursmen of the Apocalypse. He is also the most powerful of the 4 and the leader. In the past he led armies against Heaven to steal it back for Hell. Death wields shape shifting scythes to kill his foes and also carries a plethora of weapons and abilities. Redemption is a handgun that Death wields. He also has a ghost hand to pull items or himself closer to that thing. Death is also able to create time portals and he is able to split his spirit into two forms while turning his physical body into stone. If that is not enough to take on the Flood with, Death also has his reaper form that transforms himself into a larger more menacing Death form. With all of this and the powers of regeneration and accelerated healing, the Flood will have a super hard time fighting this force.
If you know anything about the gaming world, Kratos is one of the most talked about and maybe the most over powered characters in gaming. Kratos may be a mortal on earth, but after giving himself over to the God of War Ares, Kratos was given great strength to defeat his enemies. Enough strength to rip the God of Olympus a new one! After being betrayed by the Gods of Olympus Kratos takes up his daggers given to him by Ares himself, and slaughters all of the Gods. In the first game after killing Ares, Kratos becomes the new God of War. The Gods then lie to kratos...blah blah blah.... and Kratos ends up killing all the Gods and even Zues. When killing the Gods, Kratos is able to take that God's weapon to use later on. Such as Hermes' sandals or Hercules gauntlets. He was also able to climb out of Hell(Hades) three times after dying!!
From killing Gorgons, Cyclops, and Gods, Kratos is an easy pick for this "A-team to take on the Flood"!
From the Game Asura's Wrath, Asura is a demigod whose character was based off a mix of Buddhism and HInduism and is just a crazy BA. After being blamed for a murder that he did not commit, Asura goes into a rage that makes him super strong. Asura has the ability to become stronger with the more rage he has.(I guess he has never seen X-Men: Days of Future Past). He also has multiple arms that change in sizes. Asura is super powerful and can take a major beating while dishing it back! In the game Asura is able to defeat a planet sized being!
This team-up is crazy when they would get together. Everyone of these characters are in a brawling game, and that shows just how much stamina they have. The Flood fight will last for days and these individuals have the the energy to last through thousands of enemies! They all never show weakness when they are at their prime and half of these folks have a rage that will keep them going past the point of being tired. If something crazy happens, Bayonetta is there to stop time or even summon a giant demon if things are looking to grim.
So a Witch, a Demigod, a God, and one of the 4 horsemen of the Apocalypse is easily enough to fight this never ending Flood!