The main antagonist of Persona Vein. He is the Angel of Control that harnessed the powers of Yaldabaoth himself. Saklas came from the alternate timeline when Joker made the deal with the God of Control. In the past, he was originally an Osakan soldier that served Yodo-gimi and turned into a Magatsu Warrior by Amrita before slain by William. However, his spirit remained unrest due to the Amrita and indomitable, as he witnessed the decayed and growing human society over the centuries. His spirit merged with the alternate Yaldabaoth, at the same time when the Great Collapse of Code Vein happened, becoming the being known as Saklas.
Desire to challenge the Phantom Thieves in the main timeline, he created Sion as a clone of the Code Vein protagonist as a portal for them and the Knights of Control that Saklas have them joined his cause, to travel back to the present. Saklas then merged with his present self's spirit for his plans to begin and eventually confronted the Phantom Thieves and their allies. His ultimate goal is to defeat the Phantom Thieves, and end the universe alongside himself so that life and humanity won't dictate their fates. After the final battles, Saklas's existence ends thanks to Sophia's awakening for the Phantom Thieves to turn the tide, while his present self's spirit finally move to the afterlife.
- Affably Evil: A stark contrast to the corrupted adults the Phantom Thieves previously encountered in Persona 5. He is shown to be polite to his enemies despite going against them. One example is he offered the Phantom Thieves and allies some food and drinks for introductions.
- Big Bad: Of Persona Vein.
- Canon Character All Along: He's one of the Magatsu Warriors that were originally human transformed by Amrita. William slayed him before, causing his ghost to manifest due to his indomitable will.
- Contrasting Sequel Antagonist: Compare to Yaldabaoth's control over society, Saklas desires to destroy the universe and himself so that society won't be controlled by fate itself.
- Also is this to Shido since his Shadow (Samael) and Saklas's names are aliases to the Demiurge. Shido is a cruel politician wishing to control the country within corruption, while Saklas loathes corrupted politicians.
- Unlike all corrupted targets that represent their respective sins in their Palaces, alongside Yaldabaoth has all the combined sins, Saklas has none.
- Dark Messiah: Being Yaldabaoth's successor, Saklas shared this trope with the god in bringing destruction to humanity.
- Expy: His appearance is similar to Shinobu Sensui.
- Having Amrita inside him and the connections with Yaldabaoth is compared to Dartz, the Orichalcos, and the Great Leviathan (the Orichalcos God in the Japanese version). Both of them used to have deceased wives.
- Knight of Cerebus: His appearance takes a much darker turn to a different level for the Phantom Thieves unlike Yaldabaoth and the corrupted adults four years back.
- One-Winged Angel: Fuses with the Yaldabaoth Persona to become Yaldabaoth ΩZ in the final battle.
- Reality Warper: Like Yaldabaoth, Saklas's presence affects the main timeline for his plans to set in motion. When settled in Chiyoda and distorted it to his realm for the final battles, his imaginary presence is strong enough to create cognitions of fictional characters.
- Seven Deadly Sins: Again, unlike Yaldabaoth who harnessed the power of all the sins, Saklas has none of these representations.
The Lost versions of the alternate Phantom Thieves and Akechi that came from the future timeline when Joker made the deal with Yaldabaoth. Their names are Superbia Joker, Luxuria Panther, Ira Skull, Avaritia Mona, Invidia Queen, Irritum Fox, Acedia Oracle, Gula Noir, and Cavum Crow.
- Evil Counterparts: Of the Phantom Thieves.
A historical figure from Spain in the past that William encountered. Saklas first summoned her from the timeline to challenge the Phantom Thieves and their allies.
The Shadows of Masayoshi Shido, Suguru Kamoshida, Ichiryusai Madarame, and Junya Kaneshiro are summoned by Maria to fight the protagonists, but they are defeated.