Ideals and causes are used by soldiers, organizations and individuals who work or fight for what they know and believe in. These ideals and causes can be both good and evil. Individuals usally use their ideals and reasons for fighting to justifiy themselves for their actions.
Ideals and causes of individuals
The Boss originally fought for the United States and the joy she felt from war. After she went into space, she fought to unite the world and for peace not because she was a soldier, but because she chose to and wanted humanity to do their best to leave the world the way it was.
Che Guevara also known as El Che was an Argentine Marxist revolutionary. He became a major figure of the Cuban Revolution. He fought for people even if they were not his countrymen, he tried to spread his cause abroad where he met his end at the hands of the Bolivian goverment.
Naked Snake/Big Boss originally fought for his country. His patriotism for his country was so great that he was even willing to sacrifice his life if need be. However, after learning the true details of The Boss' death, his ideals changed completely. He went on to create Militaires Sans Frontières, which eventually evolved into Diamond Dogs to fight for themselves when they were needed, although Big Boss claimed that they have no specific ideals. Big Boss then went on to create Outer Heaven to give soldiers a place to call home and free them from the grip of governments that would use them as the United States used The Boss. Big Boss's will is to stop the Patriots as well as giving soldiers a reason to fight and to carry out his interpretation of The Boss's will. Later, many individuals such as Gray Fox, Liquid Snake/Liquid Ocelot and Solidus Snake either followed Outer Heaven or adopted the ideal for themselves.
Solid Snake claimed that he had no reason to fight. When Snake joined Philanthropy, he chose to fight to stop the creation of more Metal Gears and to make the world a safer place. Snake also told Raiden that he fights for change and that is his reason for fighting.
Raiden believed in the ideal of the legendary samurai warriors that taking lives of ruthless individuals could save innocent lives. Raiden said that he protected the weak, but later admitted (albeit reluctantly) that he had a darker side that sadistically enjoyed viciously killing his enemies. This darker side is known as Jack the Ripper.
Blade Wolf believed that while all people deserve the right to be free it cannot be forced on others and must be earned for oneself. He also believed that if you have to owe someone who helps you as he told Raiden during his fight with Samuel Rodrigures that his reason for helping Raiden even though he is not being forced to is because he owes Raiden a debt.
Samuel Rodrigues original ideal was to kill all extremist gangs in the name of justice while he does it to make the world safer he mainly does so because he chose to. After being manipulated by Armstrong he decided to join him and Desperado to fight extremists but he eventually had doubts of if it was the right thing to do.
Steven Armstrong, besides his belief that the strong prey upon the weak, also believed in individuals fighting for their own beliefs instead of being told what to do.
Andrey Dolzaev was a terrorist with a dealy hatred against Russia who was responsibly for attacks against St. Petersburg and Gerogia. He wanted to free Abkhazia to independent from Gerogia and Russia. He was so driven that he killed himself to destroy a Russian made plant in Abkhazia. Raiden and Courtney Collins wondered if he did it for his cause or just because he was cornered but agreed that either way it didn't excuse his actions.
Sundowner, beside his shared belief with Desperado Enforcement LLC. that the strong have a right to prey upon the weak, also believed that war is a good thing and that it has got humanity jobs, technology and a purpose, he believes that war is a part of who people are stating that the war economy started because of humanity's desire for conflict.
Khamsin seemed to believe that all should have freedom going as far to say that they must fight for freedom even if it kills him or in his words better if it cost the people their lives.
Yevgeny Borisovitch Volgin claimed that his reasons for his actions were to make the world whole again after the splitting and conflict between the Philosophers had torn the world into two. However his true goal was to get power over the Soviet Union and turn the Cold War into World War III.
Gene arrogantly believed that he had a higher calling and that those without one should follow the will of those that do obvoiusly refering to himself. He likewise implied that his belief of those without a higher calling stemmed from The Boss's sacrifice in Operation Snake Eater. He believed that he was a father figure to his soliders and was shocked when Big Boss admitted the truth that he treats his soliders callously. Gene also had a desire for conflict wanting to make a nation for soliders he called Army's Heaven which is a precursor to Big Boss's Outer Heaven.
Hot Coldman belived that humans are to weak to destroy each other if they were threatened by each other and thought that was the weak point of the deterence theory. His plan was to have an AI Weapon as a fail-safe mechanism that would respond to a nuclear threat without any remorse or guilt.
Ideals and causes of organizations/groups
The Soviet Union was founded with the intention of ensuring Karl Marx's teachings on the Communist Manifesto.
The Philosophers originally joined together to win World War II by putting all thier resources together which made a enormus sum of money which was called the Philosophers' Legacy. After the war was won the Philosophers fought over the Legacy which led up to the era called the Cold War. Although the original members died the organization still exsisted and controlled events from behined the shadows. The Philosophers were a precursor to The Patriots.
The Patriots were originally created to carry on The Boss' will. Because Zero and Big Boss could not agree what that meant, along with Zero cloning Big Boss without the latter's knowledge or consent, they became bitter enemies. Zero believed The Boss wanted a world under one order.
Sons of Big Boss belived that the world had changed after the Cold War and that conflict is needed for humans to truely express themselves and wanted Big Boss's DNA to save the Genome Soldiers from a deadly genetic disease.
Sons of Liberty is a group that have all fallen victim to the cruellty of the Patriots cruel ways and decided to fight the Patriots to free the United States from their twisted ways and kill the founders of the Patriots.
Dead Cell were originally formed to show rookies how to deal with terrorism but after the Patriots framed and caused the death of their leader Colonel Jackson after that they were framed for causing the mass murder of US alies and civilians and after the public turned their back on Dead Cell they snapped and decided to fight the Patriots and commit genocide on the public.
Philanthropy was formed to fight against the development of Metal Gears and to fight against the dictating rule of the Patriots. Their motto "To let the world be" and Solid Snake's and Otacon's talk to Raiden showed that they wanted to make the world a safer place for the future generations. Philanthropy was arguably the closest thing to fufilling The Boss' will.
Maverick Security Consulting, Inc. is a PMC whose job is to help developing countries that are either under a military coup or recovering from a war. They also want to make the world a safer place as they unoffically helped Raiden after he went AWOL and they didn't help offically not because they didn't want to but because they couldn't.
Desperado Enforcement LLC, along with their fellow PMC World Marshal Inc. and their leader, Steven Armstrong, all believe that the strong are the ones who deserve the best and that the weak are to be preyed upon.