At 250 Arge tall with 40 stories, the Orchis Tower is currently the tallest man-made structure in Zemuria. The Orchis Tower serves both as the new city hall for Crossbell City, replacing the old city hall in the Administrative District, and as well as an international hub and a trading centre. There are facilities for corporate business and conferences as well. The building is said to be stunning at night.
Construction on the Orchis Tower was completed on August 30, S.1204. Brigetta, a resident of Crossbell, states her husband was involved in the design of exterior of the tower. It was unveiled to the public on August 31, S.1204, alongside new mayor Dieter Crois' assumption of office as well as the start of the West Zemuria Trade Conference, which was held in the Orchis Tower.
The Orchis Tower's construction was funded and overseen by the Crois Family, descendents of the original tribe centred around the Sept-Terrion of mirage. The tower's true purpose is part of an elaborate system and 1000 year plan to recreate a replacement for the lost Sept-Terrion using alchemy.
The Tower stands at the center of Crossbell State, and it is connected to the various elemental Geofronts beneath the city which were designed to absorb energy from the Septium veins in the disguise of various utilities the city required such as ventilation, water processing, incineration plants and car parking. The vast amount of power is channelled through the tower's central Mystic Core (Localised as Thaumaturgical Sector), hidden in the central floors, and broadcast from the top of the tower.
Upon the combined ringing of the three artefact bells located at the Moon Temple, Sun Fort and the Stargazer's Tower, all ancient structures created by alchemists of the past, the tower receive energies relating to mirage, space and time as well, redirecting them to a fourth point on the 'cross' the Castle of Mirrors in Mishelam Wonderland. It is here that KeA, the chosen homunculus vessel would achieve her true powers and become the replacement Septerrion.
Dieter also claims the tower has a 'Soul Conversion Function' which allows him to convert himself into a form that can takeover and pilot the Aion Type-α.
The tower is unveiled for its first international conference: the West Zemuria Trade Conference. Here, nations from all over Western Zemuria gather to discuss trade and geopolitics. The Special Support Section are enlisted to help provide security for the event on the upper floors. The conference is soon threatened by a joint attack from the Imperial Liberation Front and Anti-immigration terrorists from Calvard who are after the heads of their respective countries. However, Chancellor Giliath Osborne had hired the jaegar corps Red Constellation and Samuel Rocksmith had employed agents from Heiyue. The terrorists were practically wiped out in a bloody massacre beneath the tower.
The tower is later seen as a crucial piece in the Alchemists system to activate and broadcast the powers of their artificial Sept-Terrion of Zero, KeA. The construction of historical sites around the state, existence of the cult and the Crois Family's banking and construction of Mishelam were all revealed to be part of the 1000 year plan to replace the core of their ancient civilisation. Upon the declaration of Crossbell's independence, three Aions on loan from Ouroboros descend from the sky using power granted by the new Sept-Terrion.
With the defeat of Mariabell Crois and the depowering of KeA, the tower seemingly loses its purpose and returns to general civilian usage.
With the annexation of Crossbell at the hands of Erebonia, the Orchis Tower is the seat of power for the region, overseen by Governor General Rufus Albarea. Rean Schwarzer and the new Class VII of Thors Branch Campus are dispatched to the region on a field exercise to provide extra security for the upcoming imperial inspection of the region. Dignitaries from Erebonia, including Alfin Reise Arnor, arrive via the Pantagruel to oversee the inspection.
During the first night the Tower seemingly comes under attack by enforcers of Ouroboros: McBurn and Campanella. Mcburn apparently sets the landing craft for the Pantagruel ablaze but this is later revealed to be an illusion. Rean and Sharon Kreuger ascend to the rooftop to battle the pair of enforcers but they are soundly beaten. Class VII arrive despite orders and are also defeated. Campanella reveals Rufus's Operation: Birdcage strategy and Juna soon enters a state of distress and admonishes rean for the empire's role in taking Crossbell's hopes from them before summoning the newly built Aion Type-γ II which does destroy the landing craft. The members of the society then withdraw.
Estelle Bright, Joshua Bright, Renne, Lloyd Bannings, Elie MacDowell and KeA Bannings infiltrate the Orchis Tower's Mystic Core (Localised as Thaumaturgical Sector) in order to gain information on what happened in Erebonia prior to the great wave of darkness and the beginning of the Great Twilight. The Core's functions appeared to be disabled but the central terminal is active allowing them to to extract the information after briefly confronting Mariabell Crois, Claire Rieveldt and Black Alberich. they are allowed to escape with the information.
The tower is infiltrated for a second time in order to deactivate a barrier generator located on the top of the tower which was protecting the Stella Shrine from being acessed for the Rivalries. Class VII and the Radiant Wings stage a diversion Arc en Ciel performance to divert the majority of the protective forces whilst they enter the tower from the base. the remaining Imperial Defense Force soldiers on duty attempt to apprehend them but rebel Crossbell forces keep them occupied.
Rean and his allies ascend through the now re-activated Mystic Core, confronting golems and archaisms on their way up. They face off against a curse controlled Victor S. Arseid and McBurn but are able to overcome them. Victor is freed from the curse and McBurn prepares to unleash his full power but one of Alberichs' Leviathan units gets in the way. McBurn destroys it easily, but with Severla members of the Vander Family now present, he retreats, giving a glimpse of his true form. The group reach teh rooftop and prepare to destroy the barrier genertaor but Mariabell appears and states she has no reason to get in thier way and teleports away-with the generator, leaving the path to the Shrine open.
The Special Support Section and Juna Crawford smash thier way into the upper floors of the Orchis Tower using a stolen Soldat and proceed to oust the remaining Imperial Defense Force members of Rufus' personal guard. The guards utilise an Asmodine unit, developed from the Goliath alongside the leviathan but it is not enough and they are defeated.
Later on in the operation to retake Crossbell City, the combined allied forces including Rufus Albarea confront the Simulacrum Supreme Leader and the curse controlled Ilya Platiere at the base of the tower. They are victorious but the appearance of Reverse babel leave sthem little room to celebrate. The parties remain at the top of the tower until a path through to Reverse Babel is made available by the arrival of the Arseille II, disguised as the disabled Courageous II.