I cannot call Leviathan greedy; he can hand out alms for self-aggrandizement, he can be generous if it makes those around him revere him (it probably irritates him in John, the rejection of material benefits, because such manipulation will not work with him); he loves to take away, even without needing something. He loves to demonstrate his strength and superiority.
Leviathan justifies his cruelty by the stigmatization and hypocrisy towards him and his kin, while at the same time criticizing his brethren and saying that they could have handled things better (he himself does not tolerate judgment of his decisions and says that he does not intend to justify himself to [insert any derogatory word]).
Leviathan loves to resort to violence without necessity. He can come to a compromise with someone, but later provoke a conflict and deal with the opponent. He is skilled at convincing his followers that his victims are themselves to blame for what happened and that what became of them was deserved.
If you are his ally, he will treat you with condescension, but should you question his policy, he will immediately remove the mask of friendliness, reminding you of your place.