When the BETA were first sighted on Mars in 1958, the scientific community and the world were extremely excited at the prospect of contact with an alien race. The excitement quickly turned into horror when it was confirmed that the BETA also existed on the Moon, and 1967 marked the first hostile contact with the BETA. The war began to tip towards the BETA’s favor; 1973 marked the BETA’s first landfall on Earth, resulting in what would later be the United Nations’ subsequent withdrawal of all forces from the Moon, and the next twenty-seven years would see setback after setback for the forces of humanity, as the BETA overwhelmed them on all fronts. (I take this from this source: https://muvluv.fandom.com/wiki/Unlimited/Alternative_World)
Muv Luv Alternative/Unlimited world is a weird mecha anime franchise, however it has one of the most interesting setting and world building I have ever seen. It is worth to give it a chance.
