A fictional company from SAO Alicization based in Roppongi.
Their goal is the developement and research of advanced
artificial intelligence to use it later in the military. They've created
the Underworld which houses
artificial fluctlights, AI which is conscious.
In the era of cold war, Japan is constantly dependent on the US and they're only giving them dated or used weapons.
So the Japanese came up with project Alicization.
(Rath may be a reference to Mome Raths from Alice in wonderland)