The Real Icon of Sin created by Sergeant Mark IV, is a remake of the Doom 2 Icon of Sin featuring a new Icon of Sin with a body and wings; unlike the original Icon of Sin, this version of Icon of Sin is comparatively a lot bigger, judging how the face which once seemed gigantic, now is a mere face of a demon from a decent angle just as the picture displays. The structure of its body is a combination of metallic joints and exoskeleton which absolutely no skin. It has small mechanical wings oozing out from his back. It may be mistook as its hands as well, by their slender width. The wings are spiky and sharp. You might not want to meet those wings in real life. His shoulder is disguised as a bit brown due to the vest of flesh it wears. Its shoulders are spiky too. His arms too are mechanical and have a bony composition. The elbow protrudes out of the disproportionate forearm, while the wrist and hand remain the same: pointy and sharp. As an exoskeletal embodiment, the legs too are disclosed. The crotch bones have something mesh-like fishy between the holes to keep the holes covered. The knees have comparatively bigger spikes with another layer to protect them very well. Followed by the knees, lie his demonic legs. Even though it may look like he would walk towards the player because he has legs, he won't. Its sole purpose is the same: Remain static and attack the player(s). The battle begins when the player approaches an altar with a soulsphere on it in the middle of the arena. This time, the Icon of Sin uses more attacks along with its old ones. It now uses screams that damage players unless they take cover, and it now unleashes lightning that homes in on players and deals massive damage if it hits. Also, the player no longer has to shoot the boss in the head in order to damage him. Instead, headshots simply cause the boss more damage compared to being shot on any other part of the body. The room before the battle is now a hallway with all weapons and ammo, and mega spheres on the left and right sides of the hallway. At the opposite end from where the player begins is a pentagram with a portal behind it which takes the player to the battlefield. The battlefield is now more hellish looking than before and has rockets and plasma cells littered around the map as well as soulspheres which respawn after a certain amount of time, which helps make the battle more manageable. The Icon of Sin perches at the top of a bloodfall. When defeated it sinks back into where it came and more suiting explosions come out of it followed by a massive nuclear explosion before the level ends.
- Due to the high terrain walls after which he is seen standing, what is deeper cannot be seen - There is a blood textured floor in which's center is a few feet deep hole on which the Icon of Sin stands. The floor acts as an elevator, which is why, only after the player stand just before the soulsphere pad, the Icon of Sin is visible.
- If Icon of Sin is spawned elsewhere - regardless of it being friendly or hostile - it will not attack at all. Even after excluding its ability to spawn various monsters (which is not actually its own ability), it still has the ability to discharge tremendous fireballs and other projectiles. Still, it won't attack anyone at all.