Seth Stringer (also known as Orc Of Oppression and Revolution) makes his first appearance in chapter 9 where he is being bullied by other high schoolers. As an avid fan of William Blake, a poet, painter, and printmaker of the 18th century, he is often seen with his book or quoting pieces by William Blake.
At his first appearance, Seth was believed to be acting under the orders of Professor Eames who lead a cult, but instead Seth revealed himself to be the one who was controlling Eames all along. Seth is a contractor of Orc who uses a weapon called Sluagh Ghairm which takes the form of a horn that allows him to control the expansion and contraction of the air including spatial interference.
He is a teenager who made a agreement with the devil to obtain his power and to fight with Arago. His ultimate goal and his reason for needing the Brionac (despite the fact that he can't hold its power) is unclear, however he did said "in order to eliminate the people and the system that have built this world of deception and lies" during his first fight with The White Horseman.
In chapter 80, he readily sacrifice himself and his Seed to switch place with Arago in the Lia Fáil. Due to the Lia Fáil ability, he may or may not be dead.
Seth is a medium-sized teenager with black hair and a 'pretty-boy' appearance. At the first glance he appears weak and gentle, and would not be noticeable in a crowd of people. He is often seen in his school uniform, with either a blazer or a sweater. Some times after Patchman's resurrection, Seth began to work in the police station's cafeteria in order to form a pact with Arago to help him kill Patchman.
When he is using his weapon, the Sluagh Ghairm, triangular symbols will form around his forehead and ears, and at times, wings made of an ethereal, translucent unknown matter will spread behind him.
Seth made his first appearance as a meek looking teenager who was being bullied by his fellow schoolmates leading Arago to believe that he was actually a victim of Professor Eames. After defeating Eames and seeing the building crumbling, Arago rushes in to save Seth only to find out that Seth was all along the mastermind behind it all. Thinking that Seth was being possessed Arago tries to free Seth only to realize that Seth was actually not possessed.
Seth's true personality is that of a calculative mastermind who will manipulate people to his advantage. He lives with the principle that he will not fight a battle he know he would lose. He is after the Brionac to achieve an unspecified goal; he did, however mentioned "creating a revolution" and "eliminate the world of people who had built it with deception and lies". His powers are insufficient to do so and this is why he requires the Brionac. He targets Arago to do so but realized that the Brionac was not complete and could be improved even further. To ensure that it develops even further, Seth decides to help Arago and fights beside him. He plans to take Brionac when Arago has reached the limit and use it to create a better world for himself but before that happens, he will do everything in his might to help Arago even if it takes years for the Brionac to be fully developed. Seth is highly intelligent, being able to analyze situations and powers in a short time, mentoring and keeping notes of Arago's improvement and teaching Arago about what he knows of Brionac and its origins.
In the public, Seth wears a mask of a polite, 'pretty-boy' who is shy and adorable, gaining the interests of the police women who fawns and dotes on him. He mainly addressed Arago as 'Mr. Detective', whether in public or when they are on a mission.
However, before his final fight with The White Horseman, Seth gave a friendly smile directly at Arago, possibly starting to see him as a friend instead of a mere Brionac's user. This was later strengthen in chapter 80, where he entrusted Arago with his Seed to defeat Patchman; effectively taking Arago's place in the Lia Fáil.
As an Orc's contractor, Seth possesses the seed of the horn of victory, Sluagh Ghairm (Gaelic for "war cry") which can be seen as a huge horn that Seth would carry over his shoulder. It allows Seth to control the expansion and contraction of the air and also spatial interference which allows him to move from one point to the other. The White Horseman noted that this ability specializes in long range attacks and it can be seen that when encountered in short range combat, Seth will move into defense, blocking the opponents attack and not attacking until he gets into a range where he is able to do so.
His complete control over air allows him to attack at a long range, fly, create a defensive tornado and a compressed air to block attacks, among others. He is also shown to be capable of strategic thinking to help him win his battles even if the odds are against him.
- Anam Ghairm (Spirits Cry): One of his attacks where he blows through the horn and sends a huge blast of wind which can even tear through a truck and make a hole through the ground to allow a train to pass though. It may be his strongest attack.
- Gaoth (Irish for Wind): His fastest attack where the horns appear around his arms, allowing him to "throw" them at the enemy, forming a huge cut which would slice the enemy. The attack is more precise with a wide range compared to Anam Ghairm which has a bigger impact and spreads out.
- Caislean (Irish for castle): By compressing the air around him, Seth uses it as a barrier to block out attacks. When encountered in close combat, two discs of wind similar to that of Caislean are materialized at the palms of his hands. He uses them to block the attacks of his opponent.
- Dhroichreab Aer (Irish for Air Burst): By expanding the air in a small room, Seth creates an explosion that is capable of crushing everything in the room.
- Leviathan: Create a Tornado and uses it for both offensive and defensive perposes.
- Fire Storm: A team attack in which Seth and Joe combine Anam Ghairm and Raging Flame into a flaming tornado, whilst Arago jumps through its center and launches his Gauntlet attack. Used during their fight with The Red Horseman