Buddhist devas differ from the western conception of gods and angels in several ways: Buddhist devas are not immortal. Their lives as devas began some time in the past when they died and were reborn. They live for very long but finite periods of time, ranging from thousands to (at least) billions of years.
Each of these groups of deva-worlds contains different grades of devas, but all of those within a single group are able to interact and communicate with each other. On the other hand, the lower groups have no direct knowledge of even the existence of the higher types of deva at all. For this reason, some of the Brahmās have become proud, imagining themselves as the creators of their own worlds and of all the worlds below them (because they came into existence before those worlds began to exist).
