A reality is a small part of the multiverse existing in its own space and time. As a super-spacial-temporal being, you can be part of multiple realities in a way that you may perceive as "at once". For your convenience, there is a transcend option (in the menu under your player name) providing you with information about relevent realities that have been, are or even will be, metaphorically speaking.

As time funnels often overlap and leak, most realities share a similar past and future.