Frisk is the playable character and main protagonist of Undertale. After Frisk falls into the Underground, they embark on a journey to return to the surface. Frisk is the last of the eight humans to fall into the Underground after traveling to Mt. Ebott. Frisk is not the "fallen human" named at the beginning of the game. Frisk's name is only revealed in the True Pacifist Route.
Frisk is a human child who wears a striped pink/purple and blue shirt, blue pants, and brown shoes. They have medium-length straight brown hair, short bangs, and a blank expression. Though Frisk does not show much expression in the overworld, NPCs often describe Frisk's expressions.Just like the first human, they have no stated gender and are solely referred to as "they" throughout the game.
Frisk's personality is ambiguous, allowing the player to project their personality onto Frisk. Frisk speaks to NPCs throughout the game, but the exact dialogue is not shown. NPCs dialogue boxes display "..." to show that the NPC is listening to Frisk,and some NPCs respond to questions that Frisk asks. Depending on their actions, players can interpret Frisk as merciful or merciless. Some NPCs emphasize Frisk's kindness, understanding, and grace in the epilogue.Frisk is obedient and only disallows player input when they follow someone else's instructions, such as when Sans tells them to hide behind the conveniently-shaped lamp.
Frisk's determination grants the power to SAVE[5] and heal at SAVE points. The SAVE file can be reloaded to repeat events that occur after it, but NPCs' memories are not completely erased unless a True Reset occurs. This power emerged when Frisk first awoke in the Ruins.