He's "betraying" the mission, according to her! But eventually Sebas himself is not sure why he's doing this, and it's true he is endangering their possession! Not to mention their seeing humans as lower life forms! But involving Momonga is actually the best decision! Even if his humanity is fading, he still is humandamn, say that he's betraying is crazy
Succulent: "I'm Succulent."Nabe's name made me hungry. & now it's Succulent which made me not hungry again XD