The Sorrowvirus is a chemical matter thought to be invented by Elijah Grey and is the only substance known to eradicate any supernatural/ethereal substances from our natural plane.
When Daniel North found Elijah, they first debated on their experiences with The Being and how much it has changed over the generations. Elijah states that The Being is creating a fabric tear of matter in our plane, particularly in Wakeland City, where it primarily resides.
Elijah stated that before he was a hunter, he was part of a scouting team for Hyde Street Station and it had to be abandoned near completion due to 'unexpected events' which caused several workers to either disappear, die, or suffer from hysterical blindness. He conjured a substance which he coined the Sorrowvirus of which its origin is still unknown.
The appearance of the Sorrowvirus differs for a lot of people, it often has a very iridescent shine with a dark glow, its colours vary on the person looking at it. It doesn't seem that these colours make any difference to its effect. Elijah sees it as a bright green, whilst Daniel sees it as a vivid orange. Elijah used some of the Sorrowvirus on another entity he was hunting many years ago and said it worked, but left him suffering from severe hallucinations and unearthly voices making him wanting to kill himself. Another side-effect of the Sorrowvirus caused Elijah Gray to deteriorate in his physical state, leaving him looking a lot older than he is, but it seems this has no effect on his mobility, his state of mind eventually recovered after years of isolation.
For the Sorrowvirus to work on The Being, it requires blood from a Proxy. The only living proxy left is Daniel's missing sister, who left four years ago due to a compelling need to serve The Being. Daniel has tried to capture and save her, but has failed on all ocassions.
The last of the Sorrowvirus was handed to Daniel North directly from Elijah Gray and the only additional substance that was needed was a drop of blood from a Proxy for the Being. Once the drop of blood has been placed into the container, it must be sealed up immediately as prolonged exposure to the air can cause it to combust. Once this is done, it is ready to be used and must be thrown at the base of a supernatural entity to which it will then explode. The only recorded experience of a side effect from this is from Elijah, who had severe hallucinations. He was 2 metres away from its explosion. Being too close to the explosion will draw anything into the base of the explosion like a magnet.
When Daniel confronted The Being in Hyde St. Station, he was trying to find The Being, and this led to Daniel being impaled through the heart with one of The Being's tentacles. After letting out a horrifying scream, Daniel began showing signs of the death rattle, a natural sound that suggests somebody will die within 24 hours of the sound happening. The Being slowly walked towards Daniel and bringing it's tentacle closer to him. He then tried not to look at its face but The Being was holding it's head directly against Daniel. Slowly but surely, Daniel looked at it and let out a straining laugh. He then experiences a flashback which takes him to seeing his sister and obtaining a drop of blood from her when she declares she wants a normal life, to start afresh and that she wants The Being dead. Daniel promises that her blood will kill it, so she agress. The flashback ends when Daniel grabs the container out of his pocket, and utters the words: "Derelinqui a Deo" and for the first time, The Being makes an unearthly indescribable sound, before Daniel throws the Sorrovirus to The Being's feet. An imposion occurs and a bright light appears at the base and all sound fades out as everything is sucked into this implosion. The implosion begins to subside really quickly, collapsing in on itself and letting out a shockwave at the end which cracks and destroys the surrounding floor and walls. Daniel and The Being have disappeared.
After all this happens, the Prologue (North Rising) begins, after that, the Wakeland Survivors go to look for Daniel. And they all see The Being, even the Wakeland Survivors are hunted by it. The epilogue (Purgatory) takes place after Daniel disappears.