How many monsters do I have to kill before the Genocide mode activates? [duplicate]

I've killed a whole lotta monsters in the RUINS and I'm on lvl 3 already. I'm just where you pick up the Toy Knife but I still haven't had the 'but nobody came' encounter yet. Also, I've gone back but had no more encounters. What should I do?

Solution 1:

You need to kill at least 20 monsters before you can activate your genocide route. I had to kill 24 before I could. But, word of advice, just don't go Genocide. The game remembers even if you True Reset, and there is just a whole lot of bad vibes. Anyway, the best place to find monsters to kill is at the save point 'Leaf Pile'. I hope this answer helps!