ItemIcon006 Disclaimer:

This is merely a plausible explanation for the monster(s) in this article, and may or may not be considered canon to the series.

In-Game Information

MH4U-Raging Brachydios Icon


  • Order: Saurischia
  • Suborder: Theropoda
  • Superfamily: Forefoot Fist Wyvern
  • Family: Brachy

Theorized to have grown isolated in a special environment, Raging Brachydios is a rare special Brachydios individual that has abnormal activation of its Slime Mold. Like Brachydios, Raging Brachydios is a part of the Brute Wyvern class.

Habitat Range

Raging Brachydios have been documented in the Ingle Isle thus far, as well as the Guiding Lands in the New World.

Ecological Niche

Raging Brachydios is a predator capable of taking on and even killing other large predatory monsters, just like Brachydios. In line with their chosen habitat and absurd strength, Raging Brachydios will encounter far more dangerous foes than regular Brachydios, but will fight them and potentially win nonetheless. Notably the other residents of Ingle Isle; Akantor, Teostra, Furious Rajang as well as the deviants of many powerful monster species such as Hellblade Glavenus, Dreadking Rathalos and Bloodbath Diablos. In exceedingly rare occasions, they may be forced to flee their homes due to the presence of the Black Dragons Alatreon, and the Crimson Fatalis, both of which are unnatural existences far beyond the combat capabilities of other lifeforms. In the Guilding Lands most likely competes with even more monsters, some being really powerful. This is still really hard to study since when a Raging Brachydios was sighted and hunted no other monsters were on the area, this could mean that this variant is so powerful and dangerous that most monsters prefer to leave the locale instead of risking to face it.

Biological Adaptions

Raging Brachydios have many of the same adaptions as Brachydios, however, there is a few differences between them. Raging Brachydios are extremely large compared to normal Brachydios, but are only slightly slower than them. This size difference stems from their advanced age. The main adaption that puts them apart from normal Brachydios is the large amount of slime mold found on their body. This slime mold is unusually active on its forelegs, tail, back, and head due to a strange organ known as the Immortal Reactor. This organ has a special relationship with the slime mold plus supposedly helps the Brachydios live longer. This organ is the reason why the slime mold is so active compared to normal Brachydios, making its attacks more powerful and making the slime mold breed more rapidly than before, and remains active even on the Raging Brachydios' body. This special slime mold is called Ancient Slime Mold, and acts as an explosive protection surrounding their whole body.

Ancient slime mold is not only more active then regular slime mold, but also explodes far more violently. This provides Raging Brachydios far more potent explosions that those of its peers. Indeed, these explosions are so powerful, even other blast resistant monsters, such as regular Brachydios, will die to this slime, their shells unable to withstand the sheer magnitude of these blasts. This forces Raging Brachydios to develop its own special Indestructible Ebonshell, to withstand its own explosions, lest it kill itself. This in turn provides it nigh-impenetrable protection from the natural weaponry of nearly all other living creatures. However, should the Raging Brachydios cause enough explosive damage at once, it too will be at the mercy of its offence.


Raging Brachydios are a lot more dangerous than Brachydios yet slightly slower. Due to this the Raging Brachydios makes up for the lack of speed for more powerful physical attacks.


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