Lucifer is explaining stuff to Mammon while you're still feeling confused about your sudden surprise arrival in the Devildom...

Lucifer: "Listen, you'll be the guardian of this human from now on."

Mammon: He frowned at Lucifer's decision before glancing at Beelzebub and gripping him by the shoulder before looking back at Lucifer. "Why can't Beel do it instead?!"

Lucifer thought about it a bit as he looked at Beelzebub. "Hm actually... That might be a better choice..."

Beelzebub munched on a hamburger and blinked a few times in confusion. "Hm? Me? What do I need to do?"