It's been a strangely quiet Genocide Run for this timeline you've started.

You've encountered (and killed) a very small amount of monsters. None of the boss monsters were present either, just the common ones. Froggits, Snowdrakes, those kinds...

You can't help but wonder where the hell everyone is. These common enemies are barely giving you the EXP and LV you need. Alphys couldn't have started an evacuation this early on right, right?

After hours of strolling through the underground, you reach Judgement Hall. At this point you aren't expecting to see Sans, but... To your surprise, there he is.

Something about this feels wrong...

Sans stands across from you, hands in his pockets. He grins wide at you with glowing red pupils in his eye sockets. You notice the dust covering his clothes... Dust? But that's...

........

Sans removes a hand from his pocket, then lifts it into the air. Undyne's spears rise from the ground and block the exits of the corridor.

It's starting to add up now...

The monsters didn't evacuate early. Sans killed them himself to make sure you faced him without the advantage of EXP, LV, and HP while he had those advantages for himself. It seems he gained their abilities as well...

"...I know, Papyrus. I know." Sans mutters quietly to himself. "But I'm ready... I'm not gonna let them get away this time..."

...Papyrus? But there's no one else here. Who is he talking to..? Has all this murder gone to his head?

Whatever the case, it's time to show Sans who's really in control here. With or without your LV, the time to fight is now.