Director Kakuzawa is the central antagonist of Elfen Lied. He is the head of the research center, at 70+ years old performing experiments on Diclonius. He is from a long line of Diclonius ancestry that has been watered down by inter-breeding with humans. As a result, he has no vectors and much smaller horns on his head, which he hides under a wig. His and his son's aim are in part to replenish their bloodline by mating with the Diclonii they are experimenting on (of which Lucy is the first to be able to reproduce) and thus gain power as "kings" of the new race, which would wipe out humanity and replace it entirely. He even claims to desire the position of a god of the new, Diclonius-ruled world he envisions and has rockets fired and detonated in the air to spread the Diclonius virus.
He is the father of Anna Kakuzawa, professor Kakuzawa and Lucy's Diclonius half-brother (the only male Diclonius). He turned his daughter Anna into a gigantic immobile creature with an extremely high intellect and the ability to predict the future. After capturing Lucy and revealing his plot to terminate mankind and to fill the world with Diclonius, Anna's vectors turn visible and cause an explosion on the island that releases all the captured Diclonius. Lucy cuts off Anna's arms and Kakuzawa brings out his son, Lucy's half-brother, to try and convince her to join him. But he is beheaded by her along with his son. Lucy then says that he is not a Diclonius at all, as she does not sense him like the other Diclonii, and that his horns were just the result of an unrelated mutation. She then kills Anna, who tries to avenge her father. In the anime, he is not killed, and continues with his plans. In the last chapter, a normal Anna is seen next to the gigantic creature's body.