Shagaru Magala is an Elder Dragon and the adult form of Gore Magala first introduced in Monster Hunter 4.
Overall, Shagaru Magala's body structure is similar to its juvenile form, Gore Magala. However, following the skin-shedding, its body is now covered in glittering golden scales, as well as its horns, claws and other spiky protrusions, which changed colors from crimson red / purple to dark brown. The once hidden eyes underneath the horns are also now fully opened. Its ragged-tattered wings also became golden scaly sheets that when fully expanded, resembles a star shape (more specifically, when both wings are expanded.)
Having reached adulthood, Shagaru Magala's physical abilities are greatly enhanced; they are much stronger, more agile, and most of all, more ferocious. Their usual state is like that of an enraged Gore Magala, but with more variety of attacks and evasive maneuvers. Like the Gore Magala, they primarily use their wingarms to pummel and pin prey into submission, and will frequently fly into the air and dive down to attack.
Their mastery over their Frenzy Virus is also enhanced as a result of their maturation. They no longer require the scales to see, but can utilize more dangerous and volatile virus breath attacks, fire Frenzy beams and waves from their mouth and claws, scatter pools of scales that explode after some time, and cause pillars of energy to erupt from the ground. In addition, the passive spread of their scales is much more dangerous, able to infect and wipe out entire mountains' worth of life in one go.
In Monster Hunter Frontier, Shagaru Magala is a Exotic Species and can also enter a True Frenzy state. In this state the pale areas on Shagaru turn a mix and mash of purple shades, the claws also turn purple with a sort of crystalline shine with some white. Much of the wing membranes also turn a bright shade of purple with shiny white edges, what seems to be Frenzy Crystals form on the sides of Shagaru Magala's neck, alongside more growing on the horns, and lastly a light purple and white aura radiates from Shagaru, alongside what looks like bright white sheddings flaking off it. Those last two details vanishing upon death. However unlike Gore Magala, Shagaru cannot be knocked out of its True Frenzy state, once it enters it, it shall remain that way for the rest of the hunt.
While appearing divine, like a mythical deity of sorts, it is also shown to be calm and calculating, as shown during the first encounter with the player in the Sanctuary, where it calmly scanned its opponent and recognized it as one whom it encountered in the past. However, once the monster initiates an attack, its feral and brutal nature is displayed in full force; it will chase and attack its enemies in a wild and destructive manner, unleashing everything it has until its target is dead. Being in a constant rage state that is comparable to a raging Gore Magala that can escalate even further once it becomes even angrier, its divine looks belie its monstrous aggression. Like many other Elder Dragons, they will fiercely attack all who intrude on their territory, and can easily defeat apex predators like Seregios and Barioth.
Just like when they were still a juvenile, they release Frenzy Virus to infect other monsters nearby. The reason for this is to claim territory for themselves, prevent other Gore Magala from molting properly, and to release the next generation of Gore Magala into their territory. However, the infection radius seems to be wider than ever, as the virus can be seen leaking out from its den, infecting many monsters in the Heaven's Mount. The virus strain also seems to be more intense, easily corrupting a mighty beast like Zinogre and turning pack-monsters like the Iodrome and Ioprey against each other. The dark virus aura that envelops a Shagaru Magala is so intense that it's said to dissipate only once the progenitor monster is dead.
Other from the encounter at its den in the Heaven's Mount, not much else is known about this unique and dangerous monster.
While the juvenile Gore Magalas are known to roam many places (even if they are not seen in areas like the Frozen Seaway, the monsters of that region can still get infected by the Frenzy Virus, suggesting that the Gore Magalas definitely have been around possibly during their long flights from one area to another to find more prey), it seems that they would return to shed their dark skins in order to enter adulthood high up in the Heaven's Mount, to avoid possible threats during the shedding process.
At the campsite of the Heaven's Mount, stood an ancient stone door which has been sealed and shut tight. Beyond the door is actually the nest of Shagaru Magala, which is also known as the Confined Arena or Sanctuary. It is possible that the people of the past erected the gate to keep the beasts in, or at least wanderers out. However, the Confined Arena doesn't have any walls, which allows Shagaru Magala to freely enter and exit, making the sealed door obsolete.
Apart from its secluded den in the Heaven's Mount, Shagaru Magala are sometimes spotted wandering in the Everwood. In recent years, Shagaru Magala has been seen roaming in the Citadel.