The Puppeteer (often called Peter by the party) is a high-ranking very scary Umichooan man.

He's described as a big, girthy man with eye-searing garish clothes. Most of these things seem to be a rare divergence among umichooans, however current Riung has mentioned him possibly setting it like this himself.

According to Future Riung he might have been the person who granted Victor Vituska the ability to take Gifts from other people.

In session 24, Gaia tried to ask Riung about him. At that exact moment he appeared to ask how does she know of his existance. This might have been foreshadowing that he was watching Riung

In session 26, after the party retrieved a tank core with Riung's help, the Puppeteer revealed that he watched Riung, and blackmailed her for “a future favor”. Despite almost dying to Gaia and Maelle

• According to Present Riung, he's “someone who can decide our deaths on a whim”.
• According to AMANADA, he's a “someone who we can't defeat (yet)”.
• According to Gaia, “she will kill him before he can even redeem the favor”.