Tetsuwan Atom (1980) - episode 43 - 20 Oct, 1981

Alien invaders arrive in the Sol system and begin destroying space stations orbiting several of the planets. The nations of the world believe the attacks are those of Atlas, and unite to form a World Defense Force to stop Atlas. Captain Keeley, one of the squad leaders, is tasked to destroy Atlas, which he desires as revenge for the death of his brother, a scientist on one of the destroyed stations. Astro, however, wishes to reason with Atlas, but Keeley refuses and takes his squadron out to battle. Atlas arrives to battle Keeley's squadron, and when Astro confronts him about the attacks, Atlas claims he never attacked the stations; he had come because he had heard the humans were seeking him out. He instead decides to battle Astro instead, but Livian, who was watching their encounter, begs Astro not to fight Atlas, as the two are actually brothers; Atlas and Astro were born of the same template. Astro is shocked, and Atlas goads him into joining him, knowing the truth, but Astro can't bring himself to do so. Astro has a flashback of all of their previous encounters, and he begs Atlas to make the right choice. Keeley finds Astro, and reveals his key weapon: a laser that can damage Atlas's Omega Factor. Astro rushes to find Atlas to warn him about Keeley, but Atlas refuses to run; Keeley finds Atlas and shoots him with the laser, despite Astro's begging him not to. The invaders reveal themselves, and destroy most of Keeley's squadron. Back on Earth, Dr. Elefun studies the footage of the invaders, deducing that Atlas was telling the truth. Astro tells him that he and Atlas are brothers; Dr. Elefun recalls the theft of Astro's plans and realizes Astro is correct. Meanwhile, the WDF calls an emergency meeting to strategize a plan on stopping the invaders, who are heading straight for Earth. Keeley's squadron rush back to Earth, and Astro rushes to the rescue of many civilians until he collapses from energy exhaustion. He is found and brought to an emergency shelter with Elefun. Keeley contacts him and tells him that an invader squadron is coming from Saturn, and he confesses he was wrong about Atlas. Astro swears that he will protect all those that he knows and loves, and rushes to find Atlas to reason with him again. He gets ambushed by invaders, but Atlas finds him. Astro begs Atlas to help the humans fight the invaders, but Atlas stubbornly refuses, claiming he hopes all of the humans die. Astro rebuffs him by saying that not all humans are bad, and that many are good and kind, and see past Astro being a robot. Livian reasons with Atlas, saying that Astro fights out of love and not out of hatred, but Atlas thinks he is foolish. He tells Astro to tell the humans "Perish!", but Livian shows Atlas the battle between Keeley's squadron and the invaders. Keeley sacrifices himself to destroy several invaders, and Atlas joins the fray, destroying many more invaders. They find the invader's base, and Atlas warns Astro not to join, and tells him that they are truly brothers after all. Livian stays with Atlas, out of love, and the two give their lives to pull the entire base and the invader squadron out into deep space. Astro is heartbroken by his brother's sacrifice. (Source: Wikipedia)