picture this if you will;
the universe is positively teeming with life. so much life you'd shit about it. so much intelligent life it'd make you throw up. and this life exists, for the most part, in loose confederation. but it's so diverse it'd make the raytheon annual lgbtq banquet look like the most cishet speed dating event imaginable. you have silicon life that thinks in the timescales of millions of years per thought and plasma-based neutronium dragons that live, love, and die in the blink of a relativistic eye.
so, when conflicts emerge among civilized species, what is the galactic community to do? over eons of painstaking translation efforts, almost all bureaucratic conflicts - mineral rights, murder trials, accidental courtships - are conducted through what we'd translate as the Mediated Argument Zonal Ecosystem. A case consists of two or more parties, each of which instantiate a Mediated Bipedal Platform - a humanoid thing scanned from the structure of local fauna, programmed with that species's specific viewpoints, thought patterns, ideologies, philosophies, and so on - all translated into a sort of 'universal language'. And this happens through the Mediated Time - MBPs engage in conflicts at a speed approximately 1000x as fast as human perception, which is just about average on a galactic timescale. the MBP is the least capable intermediary. it brings everyone into a roughly equal intergalactic playing field.
when a MBP is done its duty, the winner and the loser both usually dissolve. although some species archive their winners, or freeze them, or take them home to put them in a zoo. depends on the culture of the civilization. anyway.
then they beat the shit out of each other, and the winning platform advances their case. there are few formalized rules and "laws" but many norms. one of the few laws is to not litigate MAZE cases anywhere with civilized, intelligent life. backwaters or rocks only. no dark forests allowed. you participate or your species is cut off.
game theory is a universal language. it requires no specific psychology and can be described in a way agnostic of the psychological profile of a particular actor.
thus, the planet we know as Earth has been a very popular location for MAZE cases for thousands of years.
...so why is one of the local carbonoids showing up in Mediated Time? And what are they doing with that hunk of metal? And how did they gain access to MBP technology...? They aren't sapient enough to understand what's going on.
and if we've been fighting on a sentient world for thousands of years... wouldn't that nullify acres, and acres, and acres of existing case law?
Kamen Rider Gureiju (仮面ライダー灰色獣).
i'll write it eventually.