Ruins

 is the location where most of the Undertale demo takes place, as well as the tutorial area of the main game. The protagonist falls into the Underground and from a giant hole in the ground on Mt. Ebott before the beginning of the game. Toriel, a community of spiders, and many other monsters all make their homes here.

Description
are a purple, constructed region, characterized by its pathways, long halls and stone walls. There are many puzzles and traps within the, as well as a surplus of red leaves and vines that strew the area. A small river runs through the, and the dark ground is hallmarked by small patches of auburn leaves everywhere. One of the trees from which these leaves come from is located close to Toriel's Home.

Puzzles

 * See Ruins/Puzzles.

History
After the monster population was banished to the Underground by the humans, they made their first residence in what is now known as the. The King of the Monsters named this area 'Home'.

When the First Human fell into the, they were befriended by Asriel Dreemurr and were adopted by Asriel's parents, Toriel and Asgore. After the First Human's and Asriel's death and Asgore's subsequent declaration of war against humanity, Toriel took the First Human's body with her to the, where she buried the body.

Main Story
The game begins in the, with the protagonist standing on a sunlit bed of Golden Flowers.

After being attacked by Flowey, the protagonist is taken by Toriel through the, which is made up of several connecting hallways and rooms, many of which have puzzles and monsters. Partway through, Toriel asks the protagonist to wait where they are, so she can go ahead and finish something. The protagonist continues onward, finding a bowl full of Monster Candy, as well as Napstablook. In the farthest depths lies Toriel's Home, a small nest of spiders having a bake sale and one room that provides an open view onto what appears to be an old city.

Trivia

 * The golden flowers in the room where the game begins can only be examined after meeting Flowey.
 * To the right of the Napstablook fight, a small spider bake sale can be found, where Spider Donuts and Spider Cider, for 7G and 18G respectively.
 * When doing one of the 'rock pushing puzzles', one of the rocks doesn't want to be pushed (at first). If you ignore the other rocks required for the puzzle and instead keep pushing the reluctant rock, the barrier will still move.
 * In the room with three visible Froggits, the fourth Froggit, which is ant-sized, can be found inside of one of the wall cracks. This is found by inspecting the northern wall in the room.
 * If the protagonist talks to the third Froggit repeatedly, they can make it so monsters names no longer appear yellow when they can be spared. They can also switch it so the names appear pink instead.
 * If you have backtracked before leaving the Ruins, Toriel (only if you have spared her) will appear in the room where you start off in, tending the flowers.
 * If the player has killed Toriel or fled from her during her battle, then sleeping in the bed again triggers the message "(player)! Wake up! You are the future of humans and monsters." and wakes up to disturbing music, as if they had a nightmare. This also tells the player who did the latter that Toriel needs to be battled in order to proceed further in the game.
 * After leaving the Ruins, the door leading to the Ruins will be locked for the rest of the game and the only way for the door to open back up is to beat the final boss of the True Pacifist Route.
 * After completing the "Independence Test", Toriel tells the protagonist to remain in the room and gives the protagonist a Cell Phone. If the protagonist waits in the room for 5 minutes, Toriel will call them, talking about her errands "taking longer than she thought they would." Waiting another 5 minutes provides another call from Toriel, telling the protagonist that a white puppy snatched what she was looking for (Perhaps one of the ingredients to make the Butterscotch-cinnamon Pie). The next calls the protagonist receives (waiting 5-10 minutes) are from Toriel as well, but it seems that the same puppy stole her Cell Phone, and she tried to recover it. The last call triggers when the protagonist moves forward to the next room, where Toriel tells them that she got her Cell Phone back.
 * Depending on the protagonist's HP when finding her home, Toriel's dialogue before telling the protagonist to enter her home varies.
 * Full HP - "Not a scratch... Impressive! But still..."
 * Less than full HP, but more than 2 - "There, there, I will heal you."
 * 2 HP or less - "Who did this to you? You will get an apology."

Ruinen Las Ruinas Руины 廢墟