Tearfall

The full Concept of sadness, and the reason for Sadness Cults, TearFall manifests as an endless waterfall with teardrop shaped pieces of supercritical radioactive metal falling down it.

TearFall is mostly silent, but it knows things that most beings would be driven mad from learning.
It knows the reason why The Golden Gladiator is a gladiator.

This knowledge is why many Sadness Cults form.

TearFall knows things that no one should learn, and claims the only reason that it takes the form it does now is because this knowledge. More likely, it knows these things because it needed a justification for its nature.

The only contradiction I've seen to this: it cannot understand how someone could learn the things it knows and keep going, implying a time when TearFall only mourned, and could keep going.