Mt. Fuji

Mt. Fuji (富士山) is a location in Seraph of the End. It is a mountain in Japan. It is sought out by Yu who with Mika means to find a place where they can delve into memories. Mt. Fuji is in mind for creating possibly last memories for themselves, and to avoid being detected by others.

Details
Mt. Fuji is a symmetrical volcanic cone capped with snow. There is a sign reading Mt. Fuji 5th Line Station Entrance showing the pathway to the summit. The elevation is shown to be 2,400m (7,874ft).

Around the summit of Mt. Fuji is the Sengen Shrine. Where other buildings throughout the world have sustained at least some form of damage, the man-made structures around the top of Mt. Fuji are unscathed. Nearby at the bottom of the mountain are at least two rows of ruined buildings, some bearing a design of the mountain in what was a possible tourist location.

There is a forest at the base of the mountain called The Sea of Trees, also known as Aokigahara. There are large animals such as bears living there. Boars also exist in the woodland, along with multiple small birds. A lone cabin is established within this forest. This cabin has at least two rooms, with the space to store enough food to sustain Yu and Mika's memory exploration.

Although not shown, Guren had told Yu how the magnetic fields and other factors are irregular around Mt. Fuji with spells being affected by such forces.

Akihabara Arc
Mount Fuji looms in the distance as Yu and Mika drive towards it. Discussed as both a place to visit and hide in, the Sea of Trees in this part is mentioned. A pathway up the mountain is traversed by Yu and Mika as they create potentially last memories.

At the Mt. Fuji Summit Sengen Shrine, a conversation is had on which god should be prayed to. Without any specific one in mind, Yu and Mika pray to anything that could be the First's enemies. The view from Mt. Fuji is enjoyed by Yu and Mika throughout the night until sunrise. This view was one Mika never wanted to forget, and the location was where Yu said for them to bring everyone back, and have so much fun they would completely forget all the bad stuff they went through.

A cabin in the Sea of Trees is the location Yu and Mika opt for to begin accessing past memories. Yu physically remains in this cabin as he closes his eyes to join Mika who vanished into a memory of ancient Greece. A food supply in an adjacent room in the cabin is accessed by Yu to regain energy. Alone there temporarily, Yu feels elation at feeling like he is on an adventure with Mika before he returns to the memory where deeper sections have become reachable.

The base proves useful in allowing Yu and Mika to access memories from the prehistoric past where Dinosaurs were alive on the planet. This location allowed Mikaela to be seen alive in memories along with a homunculus named Yu. The cabin was returned to for Yu to eat and regain the energy needed to continue the pursuit of Mikaela in the memory.

That a Seraph Civilization was present on Earth where Sika Madu was situated in at the time was able to be observed. Seraphs including human appearing angels were forming the Tower of Babel to gather light to return to paradise was also something learned thanks to the seclusion of this location. That Paimon meant to kill Mikaela to prevent Sika Madu from being punished by God was a scenario able to be witnessed.

The cabin specifically amongst the trees around the mountain proved vital in allowing Yu and Mika to learn major details of the past. It was not just the nature of some angels which were seen for the first time in the memories able to be traversed, but also the circumstances of Mikaela's plan that factored into Yu and Mika's. After the spirit of Mikaela was seen to be active around the time when the first humans were brought to Earth, after Mikaela entered the body of a child who resembled himself in the memory, Yu had the revelation that in fact he was Mikaela.

The location of Yu having an existential crisis, the area around Mt. Fuji was also where Yu and Mika affirmed they were not the beings of the past, but were themselves. In this area, Yu would address how Mika was becoming a full demon having noticed that where he vowed he would not give up on him even if Mika entertained thoughts of leaving given the possession risk. On account of Mikaela's spirit having entered a human body to avoid himself being resurrected by Sika Madu, where the homunculus named Yu had taken on the appearance of his physical corpse, Yu and Mika decided they too would form their own campaign to resurrect everyone.

Afforded all the time they required, with no interruptions from any forces that could have been searching for them, or come across them by chance, Yu and Mika could traverse memories further back than any others accessed before. For the shock of what they had discovered, the seclusion allowed them to re-affirm a commitment to the goals that were important to them, which overcame the worries of what the purpose was to anything given the details of the past, and the concern of Mika intending to leave as he was becoming a full demon all the while. Mt. Fuji was where Yu and Mika decided their next course of action, namely to gather the seven sinful keys.

Animals such as a bear and two boars among others are gathered as food for Yu to save on rations. The woodland is also where Yu and Mika promised each they would not sacrifice themselves as they considered how resurrecting Mikaela may affect one of their lives. Given the information that others think Mika is linked to Mikaela, a plan is formed here where Mika feels confident that it will allow them to prevail without sacrifices.

From using Mt. Fuji and its surrounding area to conceal themselves from others, traversing a multitude of memories to learn vital details, and then form their own decisive plan, the location is departed from as Yu and Mika head to the Demon Army headquarters to commence their goal.

Trivia

 * is a real mountain in Japan.