- For the Neutral and True Pacifist Route counterpart and the item found at the beginning of the game, see Toy Knife and Worn Dagger.
The Real Knife is a weapon item found in Asgore's Home, replacing the Worn Dagger in the Genocide Route. Its defensive counterpart is The Locket. It is the Genocide Route weapon item associated with the First Human, and is implied to belong to them.
Near the beginning of the Genocide Route, its existence is foreshadowed and is indicated to soon be acquired during the Genocide Route.
- If the Real Knife is hacked into the inventory on a non-Genocide Route and is equipped, most monsters are able to be spared on the first turn (even most non-spareable monsters), noting that the monsters fear the hostile nature of the weapon.
- Its Steam Badge description of it makes an eerie reference to a rumor that came about from the Undertale Demo, where the Real Knife was supposedly able to be found, it describes the Real Knife as, "A symbol of the bond between player and character.", thus making a callback to that rumor.
- Within the context of the final game, Chara regards, depending on perspective, the player as their partner on the Genocide Route which could not be completed by either entity alone.
- Despite being the strongest weapon in the game, it never sees any real use without hacking as the last enemy has only 1 HP.
- It is implied that the Real Knife is the same as the Worn Dagger, but since the protagonist and Chara have higher LOVE in Genocide, it is described as a weapon rather than a gardening tool.
|Consumables|| Monster Candy • Bandage • Spider Donut • Spider Cider • Butterscotch Pie / Snail Pie|
Snowman Piece • Bisicle / Unisicle • Cinnamon Bunny • Temmie Flakes • Abandoned Quiche
Dog Salad • Astronaut Food • Instant Noodles • Crab Apple • Hot Dog...? / Hot Cat
Glamburger • Sea Tea • Starfait • Legendary Hero • Bad Memory • Last Dream • Popato Chisps
Nice Cream • Junk Food • Steak in the Shape of Mettaton's Face • Hush Puppy
|Weapons|| Stick • Toy Knife • Tough Glove • Ballet Shoes • Torn Notebook|
Burnt Pan • Empty Gun • Worn Dagger / Real Knife
|Armor|| Bandage • Faded Ribbon • Manly Bandanna • Old Tutu • Cloudy Glasses|
Stained Apron • Cowboy Hat • Heart Locket / The Locket • Temmie Armor
|Miscellaneous||Punch Card • Annoying Dog • Dog Residue • Undyne's Letter (EX) • Mystery Key|
|Cut Content||Croquet Roll • Rock Candy • Pumpkin Rings • Stoic Onion • Ghost Fruit • Puppydough Icecream|