Refers to the alternate universe United Nations of Chikyuu.
The U.N. still exists as a central world figure, but is much more active in participating, and ending conflicts occurring around the world. Prior to the events of Sekai no HERO Iwaku, it somehow eradicated war between countries, making a global era of peace under it's rule.
After the discovery that Professor Homac was actually at fault for dragging the Neo-Nubians into the earth's atmosphere, by capturing them and experimenting on their powers to create new weapons, Undersecretary Kohinata reprogrammed Gabriel-0's limiter commands, allowing him to stop Homac. Thus, the United Nations came into the control of Professor Homac's devilish creation, the Reality Breaker Trinkets, but soon lost control as Homac's sleeper agents sabotaged their transport.
The U.N. would help Gabriel-0 find the Reality Breakers and ally with them, or at least stop them from wreaking havoc. They also recieved aid from the ISAF (Chikyuu) This led them to create the EmeRAID and the Official U.N. Sanctioned Anomaly Dispersal Team Checkmater. Using their newfound allies' technology, the U.N. Developed fighting robots for the Checkmater to use - in case the Gaian Agressors use their gigantic MechaVORE monsters.
By the end of the first season, the UN used it's Sure-win Final Secret Weapon, completely destroying the last Gaian MechaVORE carrier battleship to attack earth.
Undersecretary Kohinata - is in charge of Alien and Supernatural affairs.
Unexplained Stuff Edit
It also seems to be still called 'United Nations' instead of it's japanese counterpart for some reason.