Hohoho... Fellow chara or dude behind a screen
You are up for hell of a challenge, it is hellishly hard.
So where do we start... hmmm... am i reading the script right...?
Oh here we are...yep yep....grind alot. cool we can start now
So first of all you will spawn in the ruins and please make flowey suffer for his crimes and dodge his *frendliness pellets* as that is 100% nescassry for the run.... And now you will have to run back and forth between rooms until you kill so many enemies they say "'ight ima head out" and the screen says "but nobody came" and some dude decided to put some halloween music on that as creepy as hell and totally not floweys theme but 1200% slower. Oh yeah a tip:If you want to grind enemies press up and down on a wall which makes you constanly go up and down between them letting you just press 2 buttons at once instead of having to walk back and forth.
NOW THE SADNESS BEGINS
You will need to kill toriel, you hate her so much you decide to pull up with the strongest weapon in the game, a fake knife made of plastic 😂and somehow manage to deal like 23k damage with it which is crazy brother. well that does it for the beginning of this guide. now lets move on...
uhh wait where did i leave the script again...?

We love grinding in undertale and suffering so lets do that some more
FROM NOW ON YOU WILL HAVE TO KILL EVERY SINGLE ENEMY IN EACH AREA UNTIL "but nobody came" APPEARS. Tip:at the save points after the ruins will now display #(number of enemys left to kill) so that is very useful. In hotland you can just skip to core and grind the enemys there, it will still count as the same area and make sure you don't fight mettaton until you have done the deed of killing innocents as you will then just get a very bad nuetrual ending instead if you decide too.
Now lets move onto boss fights, this one is just to help with grinding

Most bosses from now on will be a one shot. these bosses include Mettaton, muffet, papyrus, Mad dummy who turns to glad dummy, toriel, Sans when he decides to die finally, asgore and flowey when he decides to give up his determination and lose to you. These bosses are all one shots
But now lets get on to the New bosses.
First of all we have undyne the undying which you will fight at the bridge part before the real undyne fight. Monster kid is in your way so you attack him but undyne blocks him taking a lot of damage, but with determination turns into undyne the undying a way harder version of the original fight that will take a lot of skill to get by. This fight can be mastered easily if you buy a few sea tea for the part when she starts spamming arrows everywhere dramatically helping you.
The next most famous fight of them all. Mettaton neo!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! This is the hardest fight in the game which requires more skill than sans, he is super hard and even the best undertale can't beat him. wait this is all wrong. this is like not even a boss. So in reality Neo gets one shot. yep.
And now the actual most famous fight! Sans. This boss is the hardest boss fight and requires a megaton of skill to get by, but when you kill sans the game is practically over. you won and nothing can stop you now. Sans dodges 23 times and only has 1 atk and defense but due to him dodging the defense doesn't matter and so for the health. But with the power of karma on his side he ignores immunity frames. When sans says he will spare you DO NOT say spare or you will be thrown into a undodgeable death trap. Use this to heal however many times you want to, its a free turn which is infinite until you decide to continue the battle. When het starts saying about his special attack you are almost done, and when he uses the special attack, it is nothing at all and he decides to just sleep. You will want to bring the box to the FIGHT box and finally end the fight, he dodges once more but you hit him whilst he is like "did you really think you could?"and deal 99999999 damage due to the power of CHARA.
Thats really it after that you have beaten undertale genocide and can call yourself cool.

Thank you for using my guide and spending your time on it!
I hope this guide has helped you and can help you with your run for genocide!
Now its time to beg for awards lmao
But for real.
Good luck on your run, especially for sans.