The United Nations Guardians aka the UNG is the anti-terrorism and tactical peacekeeping force established by the Untied Nations. They were created by the UN out of a desire to protect the world from threats that ordinary military forces could not handle as well as a response by world leaders opposing the help of the 00 Cyborgs out of fear they were a potential threat to humanity.
In 1991, after the fall of the Soviet Union, peace talks between the US and Russia and non-nuclear proliferation treaties and discussions between nations began. Dr. Gilmore held a summit afterward with the United Nations to offer the aid of his 00 Cyborgs as a means of helping the world fight terrorism. The offer was rejected by the world leaders out of fear of losing political power to a team that could take out the armies of small nations at best or worse, having a dangerous unchecked element gain control of the entire world. While Gilmore tried to reason with the diplomats that he would see to it they would do good for the world, the UN turned their backs on the 00 Cyborgs, even after all they had done for humanity.
The 00 Cyborgs then tried to use their gifts to aid the intelligence agencies of their home countries.
But the problem became worse after 2012, when the failure of the 00 Cyborgs to save Dubai from a nuclear strike was called out by world leaders. Already in a state of paranoia after years of terrorist attacks and various other threats such as the His Voice incidents, the UN chose to set up a peacekeeping task force. Thus, the UNG was founded.
At some point the UN was unknowingly infiltrated by a willing slave of the Blessed who rose through the ranks of command and became the director. In 2016, after the 00 Cyborgs defeated The Cowboy and The Teacher, the UNG were led to believe that the 00 Cyborgs were murderers who killed innocent civilians by the Blessed's agent, trying to create an imaginary threat to regain their former glory. The UNG's forces went on a manhunt for them and relentlessly pursued them.
After the defeat of Pytor and the Blessed, the director position of the UNG's US Branch went to Commander Takeru Igarashi. This has led to the UNG being on slightly more friendly terms with the 00 Cyborgs given their aid in stopping the plot of the Blessed.
The UNG possesses highly advanced weapons technology, including armored battle exosuits called Savior Tanks.