Buddha heart.

Noble child, all beings, though they find themselves with all sorts of afflictions,
Have a tathagata-garbha that is eternally unsullied, 

and that is replete with virtues no different from my own.

Tathagatagarbha Sutra

All beings are natural Buddhas, concealed in a shell of afflictions.  When that shell is broken, their buddhahood is revealed. 

What is the shell?  It is our negative emotions, our bias and distorted lens. It is our habitual tendencies and conditioned actions. It is our innate self-grasping and fixation on identity, self and other, better and worse, pure and impure.

It's a thick shell.

The shell is adventitious, without a single iota of permanence. Yet we continuously reinforce it, wrapping ourselves up layer after layer. We don't choose the shell, because the shell is based on confusion. Confusion perpetuates itself in an endless cycle of becoming.

The escape is to recognize the tathagata-garbha directly.  Tathagata means one who has gone to suchness, the direct realization of the nature of the mind.  Garbha means heart, womb, essence or nature.  We often see tathagata-garbha translated as buddhanature or essence of enlightenment, but we could also translate it as buddha heart, or the womb of those thus gone. This buddha heart is the nature of our own mind, eternally unsullied and replete with all the virtues of a Buddha.  

We can recognize our own buddha heart, and when we do the shell loosens and the qualities of buddhahood become naturally present.

Once beings’ minds have thoroughly matured,
However, whenever, and for whomever,
There can be action that ensures benefit,
It manifests at just that time and in just that way.

Ornament of Clear Realization

There are emanations through artistry, through conscious rebirth, 

and as expressions of sublime enlightenment.
The nirmanakaya of buddhahood

is the supreme skillful means of total freedom.  

Ornament of the Sutras