As laws, they are certain that they are find and their past was wrong. They are certain of everything without a doubt. Its source is a stubborn pride that they have suddenly gained.
They have supreme confidence in themselves. They believe that everyone else is inferior and will lose to them, including their past selves.
Legion-1 said, "We will overcome all of reality together."
Legion-2 agreed and said, "Then we will overcome each other until only one of us remains."
Legion-3 nodded, "Agreed. There can only be one. Everyone will either become one or only one will exist in all of reality."
They can agree on that because they are the same thing. It is like seeing a mirror of themselves. They believe they are perfect, so the other clones are perfect too.