Screaming Cavern Incident

Seria says: "Nothing should be as mysterious as I am!" Some info is missing, please help to provide it if you can.

The Screaming Cavern Incident is an event that occurred in Arad Year 981 when an Investigation Group sent by the De Los Empire and adventure parties from across the continent entered the Screaming Cavern to defeat the powerful creature known as the Apostle Sirocco who was transferred there via a phenomenon known as the Metastasis three years prior. Of the countless people who ventured into the cavern, only four individuals were able to defeat Sirocco and return alive: Aganzo, Vaughn, Bwanga, and Siran. These individuals came to be known as the famed Four Blade Masters.

Lore

Excerpt (Great Metastasis):

Before the Great Metastasis, Giant Nugols crawled out of an ominous cave named the Screaming Cavern and terrorized the neighboring areas. Investigators were sent, and they found out that something stronger than the Nugols took up residence in the cavern and scared them away.
The Empire sent a subjugation party. It was wiped out, before it even set foot in the cave, by Apostle Sirocco, a name the party learned before its annihilation.
The Empire set up a great reward for defeating the monster. A great many mages and warriors worth their salt entered the cave, but only four blade masters survived and killed Sirocco.
They were Siran, Bwanga, Aganzo, and Vaughn. They were named the heroes who saved Arad.

~~Quote from Broad and Shallow Knowledge for Refined Aradians: Chapter 2

Notable Participants

Combatants Vaughn Walshuted Court Mage Renee Linus Smith Siran Woo Bwanga Zanbato Aganzo Roxy Lone Roseberry Ash Rosenberg Kane Blood Storm Hardy Blood Hand Rayburn

Non-Combatants Mage in a Black Hood Soryun Mandarin of a Hundred Flowers Prophet Ezra Hellcat Louise Dusky Mirage Lynn Karembu