Iblees was arrogant when God demanded the angels and him, who is a jinn and has free will, to prostate before Adam. He believed to be better than humans, because God made them from clay, but the jinn are made from fire. Sins stem from arrogance towards God and towards other people. Incidently the greatest crimes of humanity stem from arrogance amd believe of superiority of one people over another or one tyrant over his people.