|Weiss, you dumbass!|
SPOILER ALERT - Plot details for NIER follow.
The Shadowlord's Castle is a location far removed from Nier's village. Reached via a magical portal located at the roof of the Lost Shrine, the castle is where Nier and his friends fight the Shadowlord, and is the final destination players will encounter in NieR RepliCant and NieR Gestalt.
While called a castle, it actually takes the form of a 21st-century office building in a large city (most likely Shinjuku), which has been preserved by the Shadowlord and sentient Gestalts over the many centuries. It would appear the entire city is well-kept, implying that many Gestalts are sentient and have not relapsed as Nier would believe. No save points are available while inside, although the player is given the option to head back to the village courtesy of Devola and Popola.
The entrance hosts an atrium, with the way forward guarded by two birds who demand their questions be answered before going in; the door will send the party back to the start in a recursive loop otherwise. The party then pass through a ballroom, a spiraling staircase that leads to the exit where the twins are fought, and the escalator to the Shadowlord's chamber. Found in the next building over, they encounter him in a conference room filled with various old world objects, and a bed where Yonah is kept in stasis.
The castle will have to be revisited several times, as defeating the Shadowlord once awards the player with one of four endings, where both versions of Nier and Yonah are seen reunited. Subsequent playthroughs on the same file start at the point where Emil frees Kainé from her petrified state, this time granting the player a view of Kainé's dreams as well as being able to understand what Shades are saying, among other additional story changes. The last two endings, viewable after collecting all weapons, depict what transpires as Tyrann relapses.
The castle finally becomes available for access as Nier collects the five keys required for unlocking the portal at the top of the Lost Shrine. The party are teleported to an atrium atop a building, where they encounter two talking birds perched on a fountain that act as a safeguard to the door ahead.
Past the door, they meet Devola and Popola, who give Nier the option to head back to the village as if nothing ever happened. With Nier's mind made up, both groups do battle, and in the process, the twins absorb the Sealed Verses from Weiss, causing his speech to slur throughout their visit. Upon the twins' retreat, the party are greeted to a ballroom where holograms are found dancing, and slowly turn into Shades that try to keep the party out. Once the door going up is opened, the remaining Shades transform into a giant boar that corners them at the building's upper level, until the King of Façade arrives with his advisor and several soldiers. Having heard about Nier's journey from his people, they distract it long enough for the party to progress further, and are shown to have perished along with the boar in Ending B.
Devola and Popola are faced for the last time in the room ahead, where the two reveal the truth about the world to the party in the form of their notes on Project Gestalt. Weiss then remembers the twins to be androids, specially built to observe the Replicants that had grown to reject their Gestalts—the latter whom the party know as Shades. Devola is killed in the ensuing battle, causing an enraged Popola to self-destruct, taking a chunk of the office room with her and sending Emil's head to the desert. Kainé, however, believes Emil died in the blast, and takes her anger out on Nier before stopping herself.
The remaining group are met with more resistance in the hallway leading to the Shadowlord's chamber, where they spot Yonah sound asleep at the other end of the room. Before Nier could get to her, the Shadowlord emerges from the ground and blocks their path. They face Grimoire Noir first, who they quickly dispatch, but the Shadowlord is shown to possess his own magic independent from the book. As they fight, Yonah awakes, pleading with them to stop, before telling the Shadowlord she could no longer occupy her body as she hears its consciousness calling out to Nier. Despite the Shadowlord's pleas, Yonah's Gestalt makes her way to the window, exposing herself to sunlight and committing suicide.
The Shadowlord mounts one final assault before resigning himself to defeat. Nier hesitates for a moment before delivering the killing blow. Unbeknownst to Nier, the Shadowlord was what kept the rest of the stable Gestalts from relapsing. Ending A depicts Kainé's arm acting up, but she brushes it off as her having "shit to take care of". Revisiting the castle after collecting all weapons show that she had hardly made it to the door before collapsing, with Tyrann taking over her body once again.
Nier defeats the Shade, although now with Kainé on the verge of dying. Nier is then bathed in white light, where Tyrann then reaches out to him regarding the choices he can make:
- Ending C results in Nier plunging his sword into her heart, while moving in for a kiss. Her voice rings out, thanking Nier before dissipating for good.
- Ending D results in Nier sacrificing himself to save her, with no one to remember he ever existed. Kainé's memory still flashes back to Nier's figure despite this, and she cries at the thought.
Points of Interest Edit
- The documents given by the twins will disappear from Nier's inventory on subsequent runs, as will the map to the area. They can only be viewed while at the castle.
- The game will ask the player four times if they are sure about erasing their save data. Upon confirmation, the player will be shown each tab on the menu as every quest and item they have acquired up to that point is erased one by one. After the credits, the main menu will feature a Lunar Tear on the lower right corner from then on.
- Project Gestalt entailed for the soul (Gestalt) to be reunited with its body (Replicant) once the threat of the White Chlorination Syndrome has lapsed. Yonah is the only real human to be shown throughout the game, barring her appearance with Nier during the prologue.
- Devola and Popola casts magic from the stage during their second fight in a manner similar to dancing. The music even stops while the game is paused, as their moves are synced to the music.
- Unseen during normal gameplay is a basketball court to the left of the castle's atrium, viewable while playing through the World of Recycled Vessel DLC.
- The scene where Kainé beats up Nier was described by Yoko Taro in Grimoire Nier to be a "love scene" between the two.
- Emil's clone refers to the area underneath the Shopping Center as "[a] place very special to him", making him one of the few to remember Nier despite the latter having been wiped out of existence. He refers to Nier again as "[his] friend" when talking to more of his clones out in the Desert Zone.
- For his actions, (Brother) Nier came to be known as "the man who destroyed the world", per the description on the Destroyer Outfit.