The Golden Spellbook (金色の魔本 Konjiki no Mahon, lit. "Golden Magic Book", simply 金色の本 Konjiki no Hon, lit. "Golden Book") is a special type of spellbook converted from a colored spellbook through certain conditions.
In the final battle against Clear Note, even with the months of training they had, Zatch and Brago's combined strength proved inadequate against Clear's final form. Zatch and Kiyo refused to accept defeat and through their willpower and determination, their spellbook glowed a gold light. The spirits of all of the mamodo they had befriended appeared from the Mamodo World to the Human World and only Zatch and Kiyo could see them. With the Golden Spellbook, Zatch and Kiyo gained access to all of their supporters' spells including their most powerful spells (Shin-tier spells) and other spells that they may or may not have not yet unlocked before their elimination.
These are all the spells Zatch was able to utilize, in order of appearance:
- Danny's Jioruku, which restored Zatch's health.
- Wonrei's Shin Goraio Diboren, which blocked Clear's attack and significantly damaged him.
- Rein's Shin Garubadosu Aborodio, which blocked Clear's attack and significantly damaged him.
- Earth's Shin Varusere Ozu Māru Sorudon, which cut off the better portion of Clear's tail.
- Kido's Mikoruo Shin Zegaruga, which destroyed the severed tail fragments.
- Laila's Miberuna Shin Miguron, which protected against Clear's infinite horn bullets.
- Pamoon's Farusēze Bāron, which protected against Clear's infinite horn bullets.
- Victoream's Shin Chāguru Imisudon, which destroyed Clear's infinite horn bullets.
- Ashuron's Shin Doragonosu Buroa, which destroyed Clear's giant annihilation orb projectile.
- Ted's Shin Doragunā Naguru, which helped Zatch reach Clear's weak spot.
- Cherish's Shin Gurādo Ganzu Kofaru, which protected Zatch on his way to Clear's weak spot.
- Bari's Shin Doruzonis, which helped Zatch destroy the barrier protecting Clear's weak spot.
- Yopopo's Shin Yopopoi Topopoi Supopopoi, which prevented Clear from attacking Zatch after exposing his weak spot.
- Penny's Shin Suou Giakuru, which stalled Clear so Zatch could get out of his range.
- Byonko's Shin Nyushirudo, which stalled Clear so Zatch could get out of his range.
- Tia's Shin Saifojio, which completely healed Zatch, Kiyo, Sherry, and Brago.
- Kolulu's Shin Raifojio, which allowed Zatch and Kiyo to breathe in space.
- Ponygon's Shin Shudoruku, which allowed Zatch and Kiyo to follow Clear into space.
- Kanchomé's Shin Poruku, which stalled Clear long enough to allow Zatch to build up the power needed for his greatest spell.
After all this, all the Mamodo children in the Mamodo world that had taken part in the Mamodo Battle, including the Ancient Demons (along with Brago), lent Zatch their power, which enabled him to use his ultimate spell, Shin Beruwan Baou Zakeruga. With this enormous spell, Zatch defeated Clear and burned his book (his partner was saved by Shin Raifojio), saving the Mamodo World from a fate of genocide and extinction.
The Golden Spellbook appears in the anime during the battle between Zatch and Zeno but has a different effect. In episode 149, when Zatch's body glowed gold through the power of his determination, his red spellbook also glowed into a golden spellbook.
Unlike the manga version, where the Golden Spellbook gives the wielder all of the most powerful spells of their comrades and supporters, the Golden Spellbook in the anime gives the golden mamodo a massive surge of power from the feelings of their comrades.
The Golden Spellbook in the anime increased the potency of Zatch's spells (Zakeru was now as powerful as Teozakeru or greater, Zakeruga became a much larger beam, and the power of his Baou Zakeruga grew to a Shin-level spell) and the golden aura surrounding Zatch temporarily increased his speed and strength. Even after the golden aura fades away from Zatch, his spellbook remains gold but any time when the Golden Spellbook glows, Zatch gains the golden aura that empowers his strength, speed, and spells.
Zatch was able to defeat Zeno and stop Faudo's rampage through the power of the Golden Spellbook in the final episode of the anime.