Is there a god / demon lord / whatever of jealousy?

[Yqatuba]

I know there was the Runelord Of Envy but she wasn't a god?

[mardaddy]

I'd say Zon Kuthon might due. He left for the great beyond due to jealousy and envy over his sister.

He is described in the first two sentences for his entry in the Inner Sea Gods book as "...twisted, cruel, jealous god... ...represents ever-present pain, emotional darkness, consuming envy, and debilitating loss."

[Adjoint]

According to Archives of Nethys, there are three deities that have envy in their areas of concern: Zon Kuthon. Shax, and Fumeiyoshi.

Also the invidiaks (shadow demons) are literal personifications of the sin of envy. Their natural master and probably the best fit for the deity of envy was demon lord Vyriavaxus, but he was killed by Nocticula, and since then shadow demons reluctantly serve either Nocticula or Shax. You can make something out of that.

[Dark Oni]

Fumeiyoshi from the Tian Pantheon, also known as Lord of Envy. God of Dishonor, Envy, Graves and Undead.

[Steelfiredragon]

you could add Lust to that...might have to twist its definition a bit though