The eerie silence of New Home is broken only by the hum of the mysterious elevator. Your objective remains: navigate through Asgore’s home and proceed to the throne room. The red text descriptions highlight the unsettling atmosphere of your actions. Here, Flowey will reveal a chilling backstory, detailing his experiments with save states and his inability to feel. Collect the dagger and heart locket from your room; equipping them is merely symbolic at this point.
The Last Corridor awaits. Save your game, take a moment to prepare yourself mentally – this is the ultimate test. As you step into the corridor, Sans will appear, posing a poignant question about redemption before unleashing his full power. Brace yourself; your “bad time” is about to begin.
The Final Showdown: Battling Sans
The fight against Sans is notorious for its difficulty. Do not underestimate him. He starts with a deceptive, brief dialogue before instantly slamming you into the bottom of the battle box as a blue soul. React immediately and jump upwards! This is followed by a relentless barrage of bones and Gaster Blaster beams. Navigate through the bones with subtle movements – up, down to the center, then up again.
Expect to be defeated within seconds on your first attempt if you are unprepared. Immediate reaction is key. Evade the initial Gaster Blaster fire by moving out of their line of sight. When two Blasters appear on opposite sides, move to the top of the box for safety. Sans may shorten his opening dialogue if you retry the battle, so stay alert from the very start.
Check: Sans
1 ATK 1 DEF
The easiest enemy. Can only deal 1 damage.
This ironic description belies the true challenge. After surviving the initial onslaught, you’ll get a turn. Notice the purple bar near your HP – this is your Karmic Resistance (KR). Sans’s attacks inflict residual damage that depletes this bar, eating away at your HP over time. Wait for the purple bar to stop draining before using healing items to maximize their effectiveness.
The battle mechanics utilize blue and white attacks, similar to Papyrus. Remember: stay still for blue bones, move for white bones. The margin for error is incredibly tight, demanding precise timing and rhythm. Your jumps need to be just enough to clear the bones – anything less will result in damage.
When confronted with short bones at the bottom and long bones above, jump into a gap between the short bones, move to the right edge of the screen, and then leap across once the upper bones pass or find gaps to jump through.
Platforms may appear atop bone formations. Jump onto these platforms and move between them, but be vigilant for bones falling from above! Falling into the bones is often fatal. Anticipate jump locations and time your movements carefully. Sometimes, staying grounded is safer than jumping.
Sans will then unleash Gaster Blaster skulls, forcing you to use platforms to dodge. It’s often safer to stay near the bottom and only jump when a skull threatens you. Jump upwards when a skull is about to fire, then quickly descend. If two skulls target the same level, ascend to a higher platform and then drop back down promptly.
Sans blocks the player’s path in the Last Corridor, initiating the final confrontation of the Genocide Route.
This battle is notoriously difficult; expect numerous attempts. The key is to remain calm and focused. Prioritize evasion and avoid letting the situation overwhelm you. Taking a hit or two is acceptable. Adopt Sans’s cool demeanor and stay composed.
Continue attempting to attack Sans. Note that only attacking will advance the fight. Using items or any other action will not progress the battle. He will evade your attacks, but persist.
Eventually, Sans will appear exhausted and offer to spare you. Do not accept this offer! It’s a trap, and he will instantly kill you. This signals the next phase of the fight. Use this brief respite to heal using items.
He will then teleport you through various scenarios, demanding constant attention to your movements. Evade damage until he transitions you to the next attack sequence. A bone will appear beside your menu, indicating damage upon contact. Time your menu navigation carefully. As bones descend towards the bottom menu bar, identify openings to navigate through. It’s generally safer to avoid the item menu altogether if possible.
This is when he starts slamming you against the walls. Jump immediately after each slam to evade the bone attacks. When bones move vertically along the sides of the box, move to the bottom and slide horizontally to dodge.
Sans will eventually threaten his “special attack,” leading to a final, extended assault. He’ll rotate your perspective sideways and hurl you into a bone gauntlet. Swiftly and smoothly alternate between upward and downward movements until you reach the end. Immediately jump to avoid incoming bones. Evade the flashing red boxes. Finally, a circle of Gaster Blasters will encircle you, firing lasers sequentially from the right. Dip downwards initially, then move closer to the center (but not too close) and rotate in a circle to evade the laser beams.
After this intense sequence, Sans unleashes his “special attack”: nothing. He simply stands there, preventing you from taking a turn and attacking. Wait patiently, even if it takes several minutes, until he falls asleep. Then, maneuver your soul to the “Fight” button and strike!
Sans employs his infamous ‘special attack’, a moment of deceptive inaction that requires player patience to overcome.
You will finally defeat Sans, and he will weakly exit the screen, his fate ambiguous.
Moving Forward on the Genocide Path
With Sans defeated, proceed to the throne room. Visit the coffins first for a chilling message, then enter the throne room. You’ll find Asgore conversing with Flowey. The encounter with Asgore begins, but you instantly kill him without player input. Flowey destroys Asgore’s soul and pleads for mercy, also futilely. The entity controlling you is now dominant.
After brutally dispatching Flowey, a figure emerges against a dark void. She identifies herself as Chara, sharing your name. She thanks you for facilitating her return to life; your acts of genocide fueled her reawakening. She proposes destroying the world together.
WARNING: YOUR CHOICE HERE HAS PERMANENT CONSEQUENCES FOR YOUR GAME DATA UNLESS YOU COMPLETELY DELETE UNDERTALE OR ERASE STEAM DATA. IF YOU WISH TO AVOID THIS, CLOSE THE GAME AND RESET YOUR FILE NOW.
If you agree, Chara will obliterate the world with a single strike. You are now partners forever. If you refuse, she will jump scare you and destroy the world regardless. There is no escape at this point. Either way, the game will crash.
Upon relaunching, you will be met with complete blackness. Wait for 10 minutes for Chara to reappear. She will observe that you destroyed the world but inexplicably desire its return. She offers a deal: your soul in exchange for restoring the world. Refusing means another 10-minute wait for the offer to be repeated. Accepting is the only way to play again.
Congratulations on completing the Genocide Route. While this guide focused on Sans, remember to explore other endings and secrets Undertale offers for a complete experience.
