the void knight is inherently calm but if he goes to long without feeding on life energy he can become feral loosing his mind and starts feeding on everything around him until he's satisfied.
A hungry void dweller is not a good sight but a hungry void knight us frightening I have included a picture for further examination.
In his feral state his strength and speed is doubled but he looses the ability to use void energy instead he mindlessly charges at you and trys eating you with his many mouths.Though in his feral state he may be considered weaker he has the ability to eat anything nothing is out of his ability to eat his many hundreds of mouths are constantly eating the air and anything else.
Even metals previously considered indestructible are eaten up.
He may seem indestructible given that even though his armour turns into an organic substance and eats up any substance almost instantly he becomes pretty stupid relying entirely on instinct, and if you get him into a forest the first thing he does is eat the life energy and begin turning back to normal.
Given enough time abd will a void knight can learn to turn his body organic without going feral. Though when this happens he won't have the mouths. His organic tissue will resemble gue in a way for it Will be quite malleable.