Metron Seijin is a recurring alien antagonist in Ultraseven, known as the Alien Metron. He is a cunning and manipulative extraterrestrial who often uses deception, psychological tactics, and advanced technology rather than brute force. In the series, he serves as one of Ultraseven’s memorable foes, embodying the threat of alien infiltration and manipulation of human society. His most famous appearance involves attempting to corrupt Earth’s peace by exploiting human weakness and distrust.