spoiler!
not necessarily, scribble route is a bit complicated, just say he's a hard to get. his route also include therium and alvy, then after you already experience their route, scribbles' real route begin at least to my understanding. (it's still alvy route, so need to wait for future update)
and no, you won't die if you have good relationship with therium and date him (at least from what i know), you will just loop back to the option scene with blurry memory. whereas if you have bad relationship with therium, you will be fed to the snake and everybody forget you.