Serum appears as a serious man with white spiked hair and golden eyes. He dons an ornate golden mask which partially covers his eyes. He wears a long white coat adorned with golden rectilinear patterns and embellishments which is open on one side, revealing a blue and white tunic and an arm covered in wrappings. He wears matching black trousers and gloves, as well as armored boots with distinctive protective plates covering the knee. His sleeve arm also features a large golden shoulder guard which protrudes at a 45 degree angle from his arm. Serum also wears a thick red sash around his chest, worn loosely. When using the Power of the Mythus, A glowing golden wing shape appears behind him.
Serum carries a large broad greatsword fastened around his waist by a thick leather belt. the blade is almost as tall as he is and is kept within a decorated sheath ending in a gold decoration and red jewels.
Serum is the elder brother of Creha, and is one of the currently living survivors of "People of Mythus", an ancient race who had powers equal to that of Gods of Creation. A genocide of the race happened, which resulted in their land rising into space, creating a huge crater on the surface of the Earth. The Ordin siblings lost their father Zext in the process. But before he died, he gave small portions of his power to Serum and Creha.
As the only two People of Mythus remaining, Serum and Creha created life in their now lifeless land. Feeling lonely, they also created a copy of their father Zext. After they had finished, Serum and Creha began an eternal slumber. But five years before the game begins, the Zext copy gained autonomy and went out of control. He proceeded to separate Serum into two beings: one is a dark-skinned boy who later will be known as Signa Alhazen, and another retained Serum's original look. Signa was thrown onto the Earth and later was found by Orbus Alhazen.
Five years later, Serum is seen accompanying Zext and guarding him from Signa's attack. Signa is surprised when Serum blocks his attack, and feels some kind of familiarity with him. After this event, Signa is determined to fight Serum, which bothers Nayuta. When Nayuta's party meets with Zext and Serum in Oltapia Shrine, Signa engages a duel with Serum, then leaves Nayuta and Noi to chase him. When Nayuta meets with Signa again, Serum is nowhere to be seen. Signa bids a farewell to Nayuta and is never seen again until the visit to La Worg Shrine.
After Signa runs away, Serum always appears in front of Nayuta and Noi whenever they are near the Shrines. He warns Nayuta not to get involved in the matters of Terra to Nayuta's disagreement. They meet again in the highest level of Heliograd Tower. Serum declares that he has no choice but to end Nayuta's life but Nayuta just laughs and says that he knows Serum is Signa. Serum laughs and takes off his mask, revealing his face that is the same as Signa's. Nayuta explains that he knows because Serum said earlier that Nayuta can't protect his precious ones, even though only he and Signa knew about it. Then, Signa explains what happened to him after his duel with Serum. That time, both were exhausted after their duel. Then, their bodies dissolved into light and combined into the real Serum.
Later, the new Serum cooperates with Nayuta, coming into conflict with the artificial Zext. Upon defeating him, Serum and Creha stay on board the Lost Heaven as it drifts through space.
|Main||Nayuta Herschel - Noi|
|Major||Signa Alhazen - Lyra Burton - Creha - Asa Herschel - Zext di Quarius Dominador - Serum|
|Minor||Aulbath Alhazen - Mishy - Ada - Sasha - Professor Volans - Cealam - Colon - Gio - Erislet - Argol - Nemeas|
|Locations - Nayuta|
|Locations||Remnant Island - Sciencia Sea - Lost Heaven - Saint-Elysee - Tower Ruins|
|Types||Character Artwork - Concept Art - Official Artwork - Locations|