From PathfinderWiki
An alu-demon.
Type Outsider
(chaotic, demon, evil, extraplanar)
CR 5
Environment Any (Abyss)
Images of alu-demons

Source: Tome of Horrors Complete, pg(s). 154

An alu-demon is the immortal offspring of a succubus and a human. They are often sent to Golarion to seduce mortals, and are proficient at hiding their demonic horns and wings.[1]

Alu-demons are distinct from half-succubi by being born to a succubus impregnated in her true form, or by one who reverts to her true form while pregnant.[2]