Universal class is a category derived from the philosophy of Hegel, redefined and popularized by Karl Marx.
In Marxism it denotes that class of people within a stratified society for which, at a given point in history, self-interested action coincides with the needs of humanity as a whole.
Hegel believed that history was a movement tending towards the realization of "freedom" (although there is much debate over precisely what Hegel means by freedom) – which, in his own historical moment, he had held his own society to represent, or at least represent the beginning of.
For Hegel, divisions and conflicts between people were the external appearance of the internal tensions which drive the development of Spirit.
Conflict and its resolution were the ratchet by which human progress was driven steadily forwards – he once famously described Napoleon Bonaparte as "the World Spirit on horseback".