|Snake of Retaining Eyes|
|Rōmaji||Me ni Yakitsukeru Hebi|
|Height||155 cm (5'1")|
|Weight||43 kg (94 lbs)|
|Occupation||Snake of Retaining Eyes|
Founder of the Mekakushi Dan
Mekakushi Dan Member No.0
|Ability||Favoring Eyes (formerly)|
Disappeared (Implied) (Mekakucity Actors)
Becomes Snake (Manga Route 2)
Shintaro's Eye Ability (Music Route, Novel Route, Manga Route 1 & Unknown Manga Routes)
|Relatives||Kenjirou Tateyama (Father) |
Ayaka Tateyama (Mother)
Hiyori Asahina (Aunt)
Tsubomi Kido (Foster Sister)
Kousuke Seto (Foster Brother)
Shuuya Kano (Foster Brother)
|Manga||18. Kagerou Daze I|
|Novel||Kagerou Daze III -the children reason- (Children Record II)|
|“||Judging from you reaction, you don't remember me? That makes me sad. Last time, you swore that you would never forget me.||”|
—The Snake of Retaining Eyes to Shintaro
The Snake of Retaining Eyes (目に焼き付ける蛇 Me ni Yakitsukeru Hebi), formerly Ayano Tateyama (楯山 文乃 Tateyama Ayano) / Ayano (アヤノ), is a snake created by Marry Kozakura's strong wish to "never forget this Tragedy". In Manga Route 2, Ayano tells Marry to use Combining Eyes to turn her into a Medusa's snake and to give her to Shintaro Kisaragi.
After Marry completes her request, she is with Shintaro in every subsequent Route from birth to death as the source of his eye ability: Retaining Eyes, which allows both of them to be able to remember everything he sees, including past Routes. She observes nearly everything Shintaro does and can talk with him in his dreams, whenever he fully activates his ability, and after the end of a Route.
- The Snake of Retaining Eyes is a girl with long brown hair that has two red clips attached to its left fringe. Her eyes are dark brown, and she wears a white dress and a red scarf until she gives it to Shintaro at the end of Manga Route 2. She appears in her middle school's winter uniform without her scarf in Mekakucity Actors and Losstime Memory.
- In her other form, she appears as a snake with black scales and red eyes.
- The eldest child of scientist Kenjirou and archaeologist Ayaka, Ayano founded the Mekakushi Dan as its leader when the her mother adopted Kido, Kano, and Seto to research their eye abilities. Her member number at the time was "0".
- She was a good older sister who treasured all of her adopted siblings; she was even able to sense them through Kido's Concealing Eyes before she met them. When Seto brought Marry to the Tateyama household, Ayano welcomed her new sister into the family with open arms. When her parents told her that her siblings' eye abilities could lead them to danger, she was brought to tears and wished to learn the story of the Medusa to learn how to save them. To do so, Ayano, her parents, and Marry went on a trip to Marry's former cottage on the mountains. Unfortunately for them, this day coincidentally was also August 15th, and their car got hit by a landslide caused by a storm. Ayano and her parents were killed by the landslide, with only Ayano ending up in the Kagerou Daze, where her former wish about the Medusa ended up being compatible with the the Snake of Favoring Eyes. There, the Snake of Favoring Eyes showed her Azami's thousands of years' worth of memories on repeat so that she could thoroughly understand the Medusa. Ayano stated that the experience was enough to make her feel like she was going to go insane.
- During her time in the Kagerou Daze, Ayano witnessed the Snake of Clearing Eyes' deception of Azami and his new plan to create his a new master through Marry, which required killing all current snake owners, including her siblings. Once she got out of the Kagerou Daze, she immediately saw her parents' bodies and blamed Marry, who survived the accident, for all of her family's suffering. When they return home, she told her adopted siblings that they must kill Marry to be saved, causing all four of them to leave her and move out of their family home, where she then began living on her own and started planning on ways to stop the Snake of Clearing Eyes without the Mekakushi Dan's help.
- Her kind personality remained after her breakdown, as shown by how she she invites Konoha, a stranger, into her home when she finds him in need of shelter on a rainy street. Unlike in other Routes, she does not know Shintaro before he meets the Mekakushi Dan, and she initially is cold towards him because she falsely assumed that he was uninvolved with the Kagerou Daze. After reuniting with Kano and hearing about the Snake of Clearing Eyes' attack on Kido, Ayano displays remorse over her actions and opens up to Shintaro by telling him her story. Thanks to him and Hiyori, she eventually reconciles with her remaining family, including Marry. Her love for them and her strong desire to protect them continue to show during the Mekakushi Dan's faceoff with the Snake of Clearing Eyes, like when she begs Kano to let her go with him to stall their enemy.
- She has a strong affection for Shintaro after the events of Manga Route 2 and becoming his snake. When he visits her in a dream or at the end of a Route, she usually asks him if he remembers her and admits that she is sad when he cannot. She sometimes tells him her story with a smile despite knowing that he will always forget her until the Tragedy is finished.
- Favoring Eyes (目をかける Me wo Kakeru): While she was still human, her eye ability allowed her to project her feelings, thoughts, and memories to others. She refers to this ability as "the power of caring". In Manga Route 2, she primarily uses this ability to show others Azami's memories, which the Snake of Favoring Eyes showed her in the Kagerou Daze, and uses it during the Mekakushi Dan's attack on the Snake of Clearing Eyes. She presumably loses this eye ability after her surrogate life from the Snake of Favoring Eyes is used to turn her into a new snake.
- The Snake of Retaining Eyes is the first character to appear in the anime and is seen talking to Shintaro.
- Her ability as a snake has been called "Retaining Eyes" and "Imprinting Eyes" depending on translation. Her snake name's literal translation is "snake that sears into eyes".
- Ayano's (and thus the Snake of Retaining Eyes') backstory is unique in Manga Route 2 in comparison to it in other Routes:
- She meets Marry and welcomes her into the Tateyama family as a younger sister when she is a child.
- Ayano dies with her parents in the landslide and, for some reason, is the only one of the three to enter the Kagerou Daze.[note 1]
- Marry is also with the Tateyamas on their trip, but she survives the landslide. 
- She learns about the Snake of Clearing Eyes and his plan in the Kagerou Daze through Favoring Eyes instead of through her father, who never receives said snake.
- After her parents' death, the Mekakushi Dan leaves Ayano.
- Ayano does not commit suicide and is not stuck in the Kagerou Daze.
- Ayano never meets Shintaro until the present-day plot. Likewise, Ayano never meets Haruka and Takane.
- Ayano meets and befriends Konoha.
- She is sometimes nicknamed "Yaki" or "Ayaki" by the Kagerou Project fandom, which is based off the phonetic spelling of her name as a snake, Me ni Yakitsukeru Hebi (目に焼き付ける蛇, Snake of Retaining Eyes).
- She used to wear her hair clips in a cross shape when she was younger, then wore them parallel as she got older. The way her hair clips are placed may be to resemble her mother, Ayaka.
- "I say this every time, but I'll say it again this time. [...] Don't forget what happens today, no matter what." - the Snake of Retaining Eyes to Shintaro before August 15th in the Anime Route
- "I am your power, the power that was born within you long before this current you was born. Long ago, you and the queen made a vow to each other that you would never forget this Tragedy. Can you remember it now, I wonder?" - the Snake of Retaining Eyes to Shintaro after he fully activates his ability
- "So, tell me. Now that you know the tale thus far, what do you plan to do about the future that lies ahead?" - the Snake of Retaining Eyes to Shintaro
- "Today, his world is going to repeat. We'll meet, I'll lose him, we'll fight, and he'll forget it all over again... That's why I don't. Until the day come that he remembers, I'll keep all those memories safe. Until the world stops rewinding, and the moment comes when I disappear, let me you show you my feelings... just one more time." - the Snake of Retaining Eyes about Shintaro