If you go beyond the guardian sea heading east for 5 days you shall find a large expanse of baron wasteland with long blazing days and long freezing nights. Rain is so scarce here that it's a miracle just to even see it reach the ground. In fact the weather here is so harsh that practically no life can survive here. Seeing no use for the dead land the inhabitants of Valoran decided to dump all their trash and garbage here. Broken swords, scraps of techmaturgy, animal remains, cracked amour, lost dreams and broken souls are all common place here, lost to the mists of time and awaiting their inevitable erasing from the world of Runeterra.
Eventually Demacia and Noxus along with other settlements started exiling those who opposed them to the land of waste hoping they would just die there along with the secrets that could ruin their respective reigions. However even in the harshest conditions life can survive. The people here have managed to survive against the harsh weather more often than not going for weeks, months and in some cases years without food and water becoming almost as hardy as the land is harsh (which has become quite admirable to many armies as they probably need hardy soldiers). Due to the constant exiling of people from the mainland many if not all residents of this place are criminals, ex-soldiers, thieves, murderers and in rare cases scientists, craftsmen and magicians.
Culture & Craftsmanship
Along with their hardyness the residents here have also added resourcefulness and adaptive skills. being able to quickly analyze, fix, re-purpose and merge anything that winds up in the dump to the point of having legendary craftsmanship. The have some how created weapons by merging techmaturgy and fine blade craft to create some pretty cutting edge stuff (see what I did there :D). As for culture well... pretty much the entire population is atheist simply because having and believing in a deity is a luxury they can't afford when their mind is set on survival and that means either setting aside differences or death. A simple concept that sorts out the fighting between the different nationalities.