Ragnarok

Ragnarok (ラグナロク) is a satellite cannon from Mega Man Zero 4 that Dr. Weil developed, created for the sole purpose of destroying Area Zero.

Specifications

 * Model number: RF-SX12
 * Height: 72.4m (conventional)
 * Width: 231m
 * Maximum range: 900–1800 km
 * Maximum output: 30MW
 * Main armament: One Energen plasma beam, eight free electron lasers, and two Ekumaizer lasers.

Characteristics
From orbital view, Ragnarok is not only a massive satellite cannon, but in fact one the most advanced and largest space station at the time. It resembles Eurasia at some point, both having top-like structure. At the top of the structure is the control room which has a green observer, also function as the control module the cannon. On the eight directions spreading from the top are eight supportive free laser electron cannons red-steel modules mounted onto the station as reinforcement plates.

The cannon has a total of three modules: The main cannon which accounts for 1/3 mass of the whole station,  and features lots of energy-supplying pipes and a round energy booster combine with a built-in aiming structure. Two accelerator and aiming modules are symmetrically placed down after can regulate the whole module and fires refractive beams that connects and boost the main cannon's plasma beam energy even further, only takes up two minutes before completely fires off at 100% power supply, which creates large a massive plasma energy ball at the beam joints, cable of utterly decimating cities.

Ragnarok features a heavy outside security system with a strong protection layer of energy and distortion waves, which guarantees no spaceship could come close to dock, but it however has intensive support for transfer systems from Earth to it's inner structure, capable of transferring a whole battalion at the same time. Ragnarok is protected to allow only Weil to transfer unless hacking attempts were made. The inner structure is rather complex from the core module to the control room. It has relatively simple backgrounds, mainly red-yellow-green with many hazards such as holes and spikes, hanging elevator structures and many bizarre energy pulses from background. On the core room, many docking and glass windows can be seen from inside. The real core which hosts itself in the room, is rather small however, comparable to a Mutos Reploid's height, shaped like a giant sword with yellow lines run across a white colored mechanism around a purple-ish inner core.

History
When various people started evacuating Neo Arcadia en masse to get away from Dr. Weil's tyrannical regime and settled in Area Zero, Dr. Weil started Operation Ragnarok. He sent the Einherjar Eight Warriors to attack and devastate Area Zero with various attack plans to keep both the Area Zero civilians and the Resistance occupied while he finished Ragnarok's construction. In addition, he also deliberately kept the specific details of Operation Ragnarok vague in order to ensure that neither the Resistance nor the citizens of Area Zero found out about Ragnarok until it was far too late.

On December 16, Craft used Ragnarok in an attempt to kill Weil in Neo Arcadia, destroying the tower Weil was in and causing over 20,000,000 casualties. Craft also had Ragnarok charge up for a second attack, although he aborted it when he fought Zero.

After Craft's death, it's shown that Weil survived. He alerts the Resistance of Ragnarok's activity by firing a shot, and then attempts to use Ragnarok again, this time by crashing the satellite into Area Zero to destroy it. However, this attempt was sabotaged by Zero when he confronted Dr. Weil. The madman fused with the station's core to battle Zero, but Zero manages to defeat him, causing the station to break apart upon entering the atmosphere and burn up as shooting stars. Zero perishes/disappears along with the station, thus ending the Mega Man Zero series.

Ragnarok's remnants as well as Weil's soul serve as the main 'enemy' as Biometal Model W in Mega Man ZX and its sequel, Mega Man ZX Advent. In the latter, all of the remaining fragments of Model W merge to create Ouroboros, which bears a striking resemblance to Ragnarok.

Structure
Zero takes four trips to Ragnarok. First, he teleports straight to the station to charge the control room and stop Craft's attack. The second time, he is forced to break in through the Teleporter Base, and then disable the security in the Teleporter Circuit before storming the Core.

Ragnarok Control
This is Zero's first visit to Ragnarok. This place has many spike hazards with a reinforced steel background and a general surface color of green. There are also many hanging elevators and holes which represent the fact that this is the lowest point the player can reach of Ragnarok. The higher the stage set, the more background will be uncovered, leaving red energy lines on the walls and more spikes will appear as well. The only boss Zero will encounter here is Craft.

Ragnarok Core
The core is the highest habitable point and is the center of all activities in Ragnarok. There are less hazards here than in the control room. It is rather close to space where the higher layer has many docks and glass windows where even Earth can be partially seen. The ground layer is covered by a golden wall with many steel points, and the surface is mainly orange colored. The core room is the host for many resurrected boss fights:
 * Highest: Pegasolta Eclair and Sol Titanion
 * Higher: Fenri Lunaedge and Noble Mandrago
 * Lower: Popla Cocapetri and Tech Kraken
 * Lowest: Heat Genblem and Mino Magnus

Etymology
Ragnarok is a foretold battle and event in Norse Mythology where the Norse pantheon dies and the world undergoes several cataclysmic events before sinking underwater and is reborn anew; a name rather fitting for a satellite designed to destroy large areas from orbit.

Trivia

 * Ragnarok is one of the rare final boss rooms in from Zero series onwards to host all eight bosses at once.
 * Ragnarok sticks to the theme of a space station in orbit along with Eurasia and Ouroboros.