Enlightenment Beings of Mahayana Buddhism
Buddhism calls itself a "non-theistic" religion. The historical Buddha taught that believing in and worshipping gods was not useful for those seeking to realize enlightenment. Many Buddhists consider themselves to be atheists.
Yet Buddhist art and literature are richly stocked with godlike beings. This is especially true of Mahayana Buddhism. Mahayana temples are populated by statues and paintings of many characters and creatures, some beautiful, some demonic.
Enlightenment Beings
After buddhas, the most important beings in Mahayana iconography are bodhisattvas. The word bodhisattva means "enlightenment being." Very simply, bodhisattvas are beings who work for the enlightenment of all beings, not just themselves. They vow not to enter Nirvana until all beings enter Nirvana together.
The bodhisattva is the ideal of all Mahayana Buddhists. The bodhisattva's path is for all of us, not just the beings in the statues and pictures. Mahayana Buddhists take Bodhisattva Vows to save all beings. These are the Four Vows of the Zen school:
Beings are numberless;
I vow to free them.
Delusions are inexhaustible;
I vow to end them.
Dharma gates are boundless;
I vow to enter them.
The Awakened Way is unsurpassable;
I vow to embody it.
Transcendent Bodhisattvas
The bodhisattvas found in art and literatures are sometimes called transcendent bodhisattvas. They are beings who have realized enlightenment but who remain active in the world, appearing in many forms to help others and lead them to enlightenment. They are venerated and called upon for help in time of need.
Doesn't that make them something like gods? Maybe. Maybe not. It depends.
The bodhisattvas of literature and art can be thought of as allegorical representations of the activity of enlightenment in the world. In Buddhist tantra practice, the bodhisattvas are archetypes of perfect practice to be emulated and, eventually, to become. For example, one might meditate on the image of the Bodhisattva of Compassion in order to become a vehicle for compassion in the world.
So, you might be thinking, you're saying they aren't real? No, that's not what I'm saying.
What's "Real"?
From a Buddhist perspective, most people confuse "identity" with "reality." But in Buddhism, and Mahayana Buddhism in particular, nothing has intrinsic identity. We "exist" as distinct beings only in relation to other beings. This is not to say that we don't exist, but that our existence as individuals is conditional and relative.
If our identities as individual beings is, in a sense, illusory, does that mean we're not "real"? What's "real"?
Bodhisatvas manifest where they are needed in many forms. They might be bums or babies, friends or strangers, teachers, firemen or used car salesmen. They might be you. Whenever needed help is given without selfish attachment, there is the hand of the bodhisattva. When we see and hear the suffering of others and respond to that suffering, we are the hands of the bodhisattva.
Seems "real" to me.
Understanding Will Vary
It's true that transcendent bodhisattvas are sometimes spoken of and thought of as distinctive supernatural beings. There are Buddhists who worship and pray to buddhas and bodhisattvas as one would to gods.
In Buddhism, all beliefs and conceptualizations are provisional. That is, they are understood to be flawed and imperfect. People understand the dharma as best they can, and as understanding grows, conceptualizations are discarded.
We're all works in progress. Some Buddhists go through a process of believing in buddhas and bodhisattvas as something like gods, and some do not.