He deceived you. As you follow him to his "home" you find masses of ooze stuck around, some holding people that have partially changed to look more monsterous with glowing, gooey bellies and tail with a sort of goo bulb at the end... Some people even turning to look at you, as if they aim to grab you. As you turn to look at Nero, you realize what he is as his fluffy belly slickens and unclouds, revealing the translucent goo underneath, and the tip of his tail splits open as a blob of goo fills the space between the petals before smacking into a blob nearby and sucking it in, growing Nero's size proportionately. Nero was a monster that crashed down some time ago, and able to copy and edit memories of his captives, transform into whoever he sees, as well as convert people into more of his kind or dissolve them into more goo, he cunningly maintains his operation. Not all of what he said are lies though, and he might be willing to let you live as you are and keep his little secret. Though, he also offers a place alongside him if you wish, and threatens a disappearance if you make things... problematic. The choice is yours.