The beasts are maybe the most ancient creature to hunt in Thundermarch, predating recorded history and myth. The variations in their characteristics or abilities are so many that one cannot pin down a collective behavioral pattern--except for the predatory aspect.
They can be found in the wildest parts of Thundermarch, reigning over territories or even butting heads against each other over a prize. They appear to particularly enjoy sentient humanoids as prey, considering that they are known to abandon game in order to follow such creatures, rarely disengaging them even if death is apparent.
They are the reason why the Feral Wilds was conceived, and why children stay put in their homes.
Taking into account the numerous variations of the Elder Beasts, one cannot hope to record powers, for each one differs greatly from another. One could say they are physicaly very strong but that collapsed when a wiry, faster-than-the-eye-can-follow beast was encountered.
The only fact is that they are predators; a keen sense of sight, smell, and hearing seems to be their main core.