Nylusith

The Nylusith is a brethren of the Hydra, smaller and faster on account of plates on its back to catch the early morning sun.

Behaviour
It is fairly intelligent with it's heads enjoying debating with one another. Any allegiance a Nylusith takes on is defined by what it can get out of it. As a result they only attack people when hungry.

Combat
However when the do put their minds to something they can be quite dedicated to achieving it. It is almost as fast as a human, faster in its natural habitat of marshes as it is a phenomenal swimmer able to go more than twice as fast as a human and swim around lethal dangers as if they were clear water.

Its heads are each alert on their own and able to strike simultaneously. Worse, when cut off they are simply replaced by two heads within half a minuet. The only way to prevent that from occurring is to destroy the stump with fire, acid or by freezing it.

A Nylusith can also be killed by slaying its body which is done in the standard manner except that the Nylusith can rapidly regenerate.