Chris

Chris is currently living with Toriel Dreemurr.

Appearance
Chris has pale skin and lighter hair than Frisk, much like Chara. However, their eyes are perpetually in shadow, much like Kris.

In their original appearance, Chris had red eyes, spiky teeth, and wore a dark brown shirt with a yellowish-green stripe. After emerging from a pile of leaves, they had some leaves and twigs (resembling horns) stuck in their hair.

Since being taken in by Toriel, Chris has put on a dark green shirt with a pale yellow stripe. Their teeth don't usually appear to be spiked, and their eyes are usually in shadow. Occasionally they will have a rosy "blush" on their cheeks.

Personality
When confronted in the graveyard, Chris threatened the kids with death. However, in Chapter 3 this was revealed to merely be an act in an attempt to "fit in" with the monsters.

Chris seems to be very good at gauging others' reactions and manipulating them to their advantage - acting politely around Toriel and hiding their true nature.

Chris seems to have a large appetite, especially for sweets. Their favorite food is chocolate, and they are shown to eat a slice of Asriel's pie whole (without using utensils).

Frisk
Chris dislikes humans, but it seems like they don't know what to think of Frisk quite yet. They seemed puzzled by Frisk's gesture of kindness in the graveyard. In the 2021 QnA, Chris calls Frisk "a spineless baby with no sense of humor".

Asriel
Chris enjoys picking on Asriel, and getting a reaction out of him. In the 2021 QnA, Chris calls Asriel "a spineless baby with no sense of humor".

Toriel
Chris seems to enjoy staying with Toriel, saying that she provides much better cooking than their previous home. Chris is good at getting Toriel to do what they want.

Asgore
Asgore helped Chris while they were living on the streets. In the 2021 QnA, Chris says that Asgore reminds them of a trashy version of Santa Claus. However, they also say they wouldn't mind seeing him again, implying they may have a soft spot for him.

Noelle
Chris enjoys scaring Noelle, and has made her cry on multiple occasions.

Gaster
Chris seems to want to investigate what Gaster is up to, stealing his papers in Chapter 3 and asking questions in the 2021 QnA.

Pre-Story
At some point, Chris spent time in the city before making their way to Hometown.

Upon reaching Hometown, they hid in various places while scrounging for food - most notably Ice-E's, the graveyard, and the alleyway.

Chapter 1
Chris hid behind the dumpster in the alley, while Asgore brought them food in trash bags.

Chapter 2
Various monsters discussed the possibility of a creature hiding in the town. Mr. Drake recounted a story that Snowy told him about a goblin-like creature eating from the trash. Alphys believed it to be a zombie. MK, hearing this, decided to go on a Zombie Hunt.

Asriel finds a toy horse from an Ice-E meal, which leads him to believe that Chris is not a zombie after all. We learn from the Mad Ghost that Chris has been hiding in Ice-E's, and was responsible for them getting trapped in the Frost-E costume.

When the children went to the graveyard, they encountered Chris. They emerged from a pile of leaves as the clock struck midnight, along with the rising of a blood moon. They pretended to be a zombie in order to scare the children away, but Asriel fainted instead. Frisk tries to befriend Chris by offering the toy, but Chris takes the opportunity to run instead.

Chris gets chased by Undyne, and eventually gets cornered. They get taken to the police station, where it is decided that Toriel will take care of them. When asked their name, they initiate a survey (much to Gaster's surprise) in order to come up with a pseudonym. They go with the name "Chris".

Trivia

 * In Undertale, there are three "jokes" you can tell to Woshua: A kid who slept in the soil, a kid who ate a pie with their bare hands, and two kids who played in a muddy flower garden.
 * In chapter 2, Chris slept in a pile of dirt and leaves. In chapter 3, they eat a slice of pie with their bare hands.
 * When asked if they are a human, they responded with "Something like that!"
 * This was also their response when Asriel asked if their biggest fear was themselves.
 * In the 2021 QnA, Chris gives two fake backstories.
 * The first is that they were an orphan pickpocket, which is a reference to Oliver Twist.
 * The second is that they were created in a laboratory from human parts, which is a reference to Frankenstein.
 * When asked why they do not show their eyes, their answer is that "you wouldn't like them very much".
 * Chris appears to have a rather nihilistic view, believing no one deserves anything in life.
 * Their favorite food is candy - specifically chocolate, black licorice and sour patch kids.