He had a jealous side: when his father Josui died, he expelled Matabei GOTO, the bravest warlord in the Kuroda retainers with many military exploits who had received daimyo-level hospitality from Josui; and furthermore, he carried out measures called hokokamae (a kind of punishment).
嫉妬深い一面があり、父如水が死去すると、黒田家随一の勇将で武功も多く、如水から大名なみの厚遇を与えられていた後藤又兵衛を追放し、さらに奉公構という措置を取った。