Yaldabaoth

"Trickster... Welcome to my Velvet Room."

- 'Igor' greets the protagonist

Yaldabaoth, also known as the Holy Grail, Malevolent God, Prison Master, and Warden is the main antagonist and final boss of Persona 5. He is the manifestation of humanity's wish for order and control and considers himself to be a god.

Yaldabaoth represents all of the Deadly Sins.

Appearance
Yaldabaoth in his true form appears as a large white mechanical life form. His central body resembles the Holy Grail by its shape. Above his head is a Halo and on both sides of him are large red and golden wings.

As the Holy Grail, Yaldabaoth first appears as a Large black machine in the shape of the Holy Grail. This form progressively turns into the color gold as the Public feeds its distorted desires into Yaldabaoth

Personality
Yaldabaoth talks about humanity in a cold, insensible, and undemonstrative way. He also treats everyone as below him, like he is the supreme being. Yaldabaoth is typically described as malevolent by Lavensa.

Before the Game
Yaldabaoth was created as the Treasure of Mementos, a manifestation of Humanity's wishes to be ruled over. The public's cognition turned Yaldabaoth into a God. Yaldabaoth saw the corruption of humanity through the Deadly Sins and decided that Humanity should be met with ruin. Igor, the proprietor of the Velvet Room, disagreed, believing that humanity could be saved. Yaldabaoth, too prideful to proven wrong, absorbs the Velvet Room into Mementos. From there, he imprisoned Igor and split Igor's Assistant, Lavensa, into two twin wardens known as Caroline and Justine, who were taught that humanity should be punished. From there, Yaldabaoth decided to conduct an experiment to decide if humanity should be perished or saved. He put two people against each other in a game, that he rigged for his outcome. The first was Goro Akechi who represented the Public's Distortion. If he won, then humanity would be met with ruin. The second was the protagonist who would become a trickster and rise against the corruption of society. If he won, then Humanity would be saved. Yaldabaoth would end up rigging the outcome however in his favor.

Prologue - Final Heist: Mementos
Yaldabaoth installed the Metaverse Navigator on the protagonist and Akechi's phones so they could navigate through palaces. The protagonist first meets Yaldabaoth when sleeping his first night in Tokyo. Yaldabaoth disguises himself as Igor, claiming to be Igor himself, which he does for most of the game. Yaldabaoth observes the Protagonist's process, which Yaldabaoth calls the protagonist's "Rehabilitation" as he forms the Phantom Thieves and takes down each Palace Ruler, steadily giving the protagonists more help, eventually leading him Mementos, the Palace of Everyone's Hearts. There The Phantom thieves find the Holy Grail (Yaldabaoth) at the core of Mementos. The Phantom Thieves try to fight The Holy Grail, but due to the corruption of Society, The Holy grail was constantly being healed, making it impossible to defeat. From there, Yaldabaoth realizing he can't be beaten, fuses Mementos and the Real World, causing the Phantom Thieves to disappear due to them not being relevant in the Public's Cognition.

After Mementos
After Disappearing, the Protagonist wakes up in The Velvet room where Yaldabaoth informs him that he lost the game. Much to the surprise of even Caroline and Justine, Yaldabaoth sentences the protagonist to death, stating that the defeated must forfeit his life. The protagonist ends up standing up to Yaldabaoth and then twins, fully awakening his rebellion as shown by his prison door disappearing. Caroline and Justine end up fighting the protagonist and beating him badly, however before they kill him they start to regain their memory and thus refuse Yaldabaoth's orders to kill the Protagonist. The twins then Order to be fused together by the Protagonists, which recreated Lavensa. From here, it is finally revealed that "Igor" was actually Yaldabaoth all along. Yaldabaoth temps the protagonist with worldly desires such as fame, however, the protagonist refuses, forcing Yaldabaoth to leave the Velvet Room, which in return frees the real Igor. Yaldabaoth then returns to his temple in the now fused world, watching the ruin of humanity as all who aren't relevant to the public's cognition disappearing. The Phantom Thieves, after restoring themselves in the Public's Cognition, make their way to Yaldabaoth's temple, where they refight the Holy Grail, this time able to disconnect the tubes that feed Yaldabaoth his never ending life. The Phantom Thieves were able to defeat The Holy Grail

Final Battle
Yaldabaoth, after being defeated as the Holy Grail, Reveals his true form and confronts the thieves, throwing them all into the final battle. in this battle Yaldabaoth releases the Deadly Sins onto the Phantom Thieves for his main attacks. After a long hard fight, Yaldabaoth ends up releasing a super attack that the thieves stand no chance against, thus they fall. The Phantom Thieves weren't about to give up as their determination drives them forth. This awakens the public's eyes as they all start to remember the phantom thieves and the great things they've done. As hope is poured into the Phantom Thieves, the protagonist initial persona, Arsene reappears as the protagonist is having his Second Awakening. Yaldabaoth mistakes this as the protagonist failing to harness power, however, he is interrupted as Satanael appears. Yaldabaoth tries to use the super attack on the thieves again, however, it is seen that Satanael has protected the thieves, making them immune to it. The protagonist then uses Satanael's Sinful Shell to end Yaldabaoth once and for all. After Yaldabaoth is defeated, he turns into the  Actual Holy Grail which the protagonist steals, erasing Mementos and the Metaverse as a whole.

History
Yaldabaoth in Gnosticism is viewed to be the Evil God portrayed in the Old Testament

Trivia

 * While disguised as Igor, Yaldabaoth is never referred to as Igor by anyone but himself. The Twins simply call him Master. The Confidant Menu calls him the Prison Master. In the credits, his voice actor is listed to voice "Warden"
 * When disguised as Igor, a few differences can be noticed between him and the real Igor. His voice is much deeper than Igor's voice. He talks about humanity in a much colder attitude than Igor. When first speaking to the protagonist, he calls the Velvet room, his Velvet Room, which Igor has never done.