The story revolves around Duke Fleed who is a survivor of the Vega Star, raised by Dr. Umon as his adoptive son, and known as Daisuke Umon on Earth. Years after his arrival, he's faced with the threat of King Vega and his army, who want to conquer the Earth. With his friends Koji and Hikaru (and later his kid sister Maria Grace), Duke decides to fight back using his best weapon, the almighty Grendizer.
| Title | Time | |
|---|---|---|
| 1 | Brothers of the Universe | 1975-10-05 |
| 2 | Prince of the Other World | 1975-10-12 |
| 3 | The Tragic Fiesta | 1975-10-19 |
| 4 | The Island of Fear | 1975-10-26 |
| 5 | The Pitfall of Death | 1975-11-02 |
| 6 | Attack on Perlepolis | 1975-11-09 |
| 7 | The Feast of the Wolves | 1975-11-16 |
| 8 | The Radars are Off | 1975-11-23 |
| 9 | The Black Moon Camp | 1975-11-30 |
| 10 | Vega's Spy | 1975-12-07 |
| 11 | The Day when the Sun will Stop | 1975-12-14 |
| 12 | Blood on Snow | 1975-12-21 |
| 13 | By Iron and by Fire | 1975-12-28 |
| 14 | The Day of the Rising Sun | 1976-01-04 |
| 15 | Red Akerae | 1976-01-11 |
| 16 | The Fiancé of Death | 1976-01-18 |
| 17 | The Infernal Ride | 1976-01-25 |
| 18 | The New Time of the Caves | 1976-02-01 |
| 19 | The Crushed Town | 1976-02-08 |
| 20 | Earth in Danger | 1976-02-15 |
| 21 | The Submerged Continents | 1976-02-22 |
| 22 | The Slayers of the Sky | 1976-02-23 |
| 23 | The Flood of the New Worlds | 1976-03-05 |
| 24 | The Enforcer | 1976-03-12 |
| 25 | Fleed's Lovers | 1976-03-19 |
| 26 | The Edges of the Abyss | 1976-03-26 |
| 27 | Win or Perish | 1976-04-04 |
| 28 | The New Masters of Darkness | 1976-04-11 |
| 29 | The Fire Bird | 1976-04-18 |
| 30 | The Lightning Rock | 1976-04-25 |
| 31 | A Dreamer from Outer-Space | 1976-05-02 |
| 32 | The Ghost Queen | 1976-05-09 |
| 33 | The Wings of Death | 1976-05-16 |
| 34 | The Mercenary of Oppression | 1976-05-23 |
| 35 | The First Raid | 1976-05-30 |
| 36 | The Invincible Cosmos | 1976-06-06 |
| 37 | A Star is Dead | 1976-06-13 |
| 38 | Darkness Makers | 1976-06-20 |
| 39 | The Patrol of Eagles | 1976-06-27 |
| 40 | The Awakening of Volcanoes | 1976-07-04 |
| 41 | Baptism of Fire | 1976-07-11 |
| 42 | Peril in Abode | 1976-07-18 |
| 43 | The Victory of Eagles | 1976-07-25 |
| 44 | When Dogs are Loosened | 1976-08-01 |
| 45 | Ants and Men | 1976-08-08 |
| 46 | The Ballet of Sharks | 1976-08-15 |
| 47 | The Ignited Lake | 1976-08-22 |
| 48 | World in Fusion | 1976-08-29 |
| 49 | The Last Survivor | 1976-09-05 |
| 50 | The Four-Headed Eagle | 1976-09-12 |
| 51 | The Black Star | 1976-09-19 |
| 52 | The Generation Of Monsters | 1976-09-26 |
| 53 | The Beast | 1976-10-03 |
| 54 | The Snake | 1976-10-10 |
| 55 | The Loch Ness Monster | 1976-10-17 |
| 56 | The Lynx of Outer-Space | 1976-10-24 |
| 57 | The Monster And The Child | 1976-10-31 |
| 58 | The Lookalike | 1976-11-07 |
| 59 | The Commando | 1976-11-14 |
| 60 | Rats | 1976-11-21 |
| 61 | Pegasus | 1976-11-28 |
| 62 | Swans | 1976-12-05 |
| 63 | The Polar Bear | 1976-12-12 |
| 64 | 5 Minutes To Die | 1976-12-19 |
| 65 | A Great Between The Greats | 1976-12-26 |
| 66 | Death Comes From The Sea | 1977-01-02 |
| 67 | Diving Operation | 1977-01-09 |
| 68 | The Great Pain | 1977-01-16 |
| 69 | Like Father, Like Son | 1977-01-23 |
| 70 | The Imposter | 1977-01-30 |
| 71 | Best Friend | 1977-02-06 |
| 72 | Princess In Love | 1977-02-13 |
| 73 | For The Love Of Earth | 1977-02-20 |
| 74 | This Is Not Goodbye | 1977-02-27 |
