???

In it's natural state, it is simply a shadow with an ego ("I think therefore I am") as well as a 'foreign soul'.

It has no sekham* and must absorb a certain amount periodically in order to continue "existing" in non-native dimensions (and since its dimension ceased to exist after it left it has no means of returning to recover its natural sekham).

That is, take it from of ones who exist within the dimension it happens upon (for non-native sekham will not allow it access to the natural flow and fuel its current existance). It must and will periodically feed as it can only stay in one form for so long at any point in time (though after a "cool down" period it can return to that form if it wishes). 

It is unknown how many beings it has absorbed and taken the form of.

It is known that the only ones it seems to target are ones who have tainted their own soul (most often caused by murder). To those that have had their souls tainted by the actions of others, it offers them a chance, if they wish, to "reset" their soul as it has the ability to devour the taint and return their complete soul, purified, back into the life cycle. However, in order to do so it must devour their sekham and kaht (natural body) -- ending their current existance.

*chi, ki, orgone, prana, pneuma, life force, etc.