Boethiah

"Prince and Lord of Darkness, God of Terror, King of the Undead, the Deadman, Undertaker of Souls, the Phenom, the Master of the Mind Games, Many are our lord's lofty names, but they befit only us mortals. He controls Darkness and he also loves and enjoyment of the mortals in terror"

- Priest of Darkness

Koagorath or Kaggorath (in Daedric script, ) is the Daedric Prince of Darkness, Terror, Horror, and UnDead. His realm in Oblivion and Skyrim is known as the Darkness Hell. Same mortals believes that he was the King of the Deadra. He also known as the Deadman, the Undertaker, the Phenom, and the Master of the Mind Games. He also have loyal brothers, Molag Bal, Daedric Prince of Domination and Hermaeus Mora, Daedric Prince of Knowledge.

Personality and traits
Like all Daedra, Koagorath is known as the one of the powerful daedric prince, which Jyggalag become the second most powerful daedric prince. He is traditionally depicted as a strong red-suit with capped, warrior with bones on chest and have a bony crown. Koagorath is most scariest and demonic daedric prince, In Oblivion, he was known as the Deadman or mostle known as "The Phenom". The mortals was that Koagocath wants "respect" and follow his rules.

Even among scholars, who thinks that Koagorath is the "only" one is that a demon, which the mortals that he was 'Demon of Darkness'. Koagocath is one of the Daedric Princes consistently viewed as evil in the traditional sense; an them only for the entertainment of spilling their blood and he likes the enjoyment of mortals in terror and fear. Dnd is known to turn on his champions when it suits him, or just for the enjoyied of it. He was a brother to the Deadric Princes Molag Bal and Hermaeus Mora. Koagocath is also known for delights in visiting death and destruction upon mortals, whom he actively strives to torment.

Second Era
During the exodus of the start of Septim Empire, It's confirmed that he was Atorias Septim born to the Tiber Septim who is Emperor, he was named Prince or Second heir to the throne. The Prince was brave, honor and survived many duels and fights which he was wounded a lot. But Atorias was not afraid of the fight. Although he was born a Breton before he was made into a Immortal Daedric Prince. Atorias was battled to the death againist, Daedric Prince Jyggalag, Jyggalag wounded Datollod. Jyggalag leaving Atorias's bleeding to death. Which wounded Atorias wants to contuned the battle agianist Jyggalag. Jyggalag can tell that Atorias, the Prince of the Septim Empire are brave. After one day duel, Jyggalag keep wounded Atorias, and he lost to Jyggalag, which the Daedric Prince of Order keeps the Prince Atorias alive. Atorias was given the gift of immortal Daedric Prince (like the Hero of Kvatch ended up, Lord Sheogorath, Daedric Prince of Madness) he accepted it ended up Died of wounds, the remains of Atorias transformed into the Daedric Prince Koagocath, who controlled Darkness, Horror, Terror and the Undead.

Cultural development
Koagocath is one of the four Daedric Princes (along with Azura, Boethiah and Mephala) directly responsible for the existence of the Dunmer as a distinct race.

Since he is the only Dunmer Daedric Prince, that change the race since he was a Breton before he was Daedra. These however lamented their mortal existence as being caused by the trickery of Lorkhan. Koagorath beside along with but Boethiah approached a group of Trinimac's followers and began preaching to them an alternative viewpoint: that the Aldmer were weak and unworthy of their immortality, and that their mortal existence was a trial which all mer had to endure. (The Dunmer often refer to their mortal lifetime as The Testing.)

Along with between Koagorath and the dunmer people, the Dunmar thinks that Koagorath become a evil-voliet Deadra towards mortals, but when the Dumner summoned Koagorath, he become impressed with the dunmer.

Roles in religion
Koagorath continued to play a key role in the religious practices of the Chimer even after they became the Dunmer along with Boethiah. He is one of "evil" and "good" daedra out of Boethiah, Azura, and Mephala.

Third Era
Sometime in 3E 433 where Koagorth and Dagon sought to conquer all of Tamriel. In order for Dagon's Forces to invade, however, the Emperor and his heirs had to be removed. This task fell to the Mythic Dawn, who succeeded in assassinating Emperor Uriel Septim VII.

The Hero summoned Koagorath in his shrine, he told the Hero that Lord Harkon stole his urn. In the quest, "No One Stole the Urn" when the Koagorath told the Hero that he stold this urn, where the Hero killed Harkon, after the Hero returned to the shrine, Koagorath was inpressed with the Hero—but Koagorath rewarded the Hero his own Urn.

During the Oblivion Crisis, Koagorath helped Mehrunes Dagon invaded Imperial City, both Koagorath and Dagon tried to stop Martin Septim for relighting the dragonfires. But it was to no avail; using the magical Amulet of Kings, Martin summoned/merged with Akatosh and banished Dagon back into Oblivion, and with him the whole of the Daedric Forces of Destruction.

But Koagorath battles with Martin in duel, ending up wounded Martin, as Koagorath grabs Martin by neck, the Hero of Kvatch saves Martin and defeated him and Koagorath was vanished into Oblivion, wounded.

Fourth Era
During the events of Skyrim in 4E 201, the Dragonborn summoned Koagorath, and he wants to is kill the Vampire Rebel Lord, Count Vlad who is tried to kill him or vanished Koagorath back to his realm for good. After the quest, he rewards the Dragonborn a Darkness Robe, a unique robe that does 15 percent damage on the enemy's health, makiska and stanmia damages. In Dragonborn, Miraak, a Dragon Priest returns and sent same assassins known as "" to kill the "False" Dragonborn. Upon this descision, the Dragonborn summoned Koagorath to help him to defeated Miraak, he wants to think about it. After the Dragonborn was accepted to have Mora by his side, the Phenom Koagorath appears and said that he'd accept the dragonborn help. After Miraak tried to make a death escape by jumping into the waters of Apocrypha. But it was inturrepted by Mora's tentacles, Koagorath appeared and stabbed Miraak in back, and he died of wounds. Then he want to give a soul to himself, but Koagorath give the soul to the Dragonborn.

Creator and patron deity
As ruler/king of the UnDead, Koagorath is who ruled all the Dead, for example Draugr, Ghost, Skeleton and Zombie (in Dawnguard). Koagorath is known as the Deadman, and UnDead King. Some say that Koagorath controlled the Dragon Priests. In the book The UnDead King told the story of Koagorath became King of UnDead and controlled the Undead.

Some say that he created the Undead, after their loved ones turned against their lovers after they died. The famous dead Kings were Undead like King Lysandus, Olaf One-Eye, and much more.

Evolution
The most common undead creature are mainly Lysandus, Olaf One-Eye, Hakon, and much more.

Plane of Oblivion
Koagorath's realm in Oblivion is called the Darkness Hell or the mortals call it "The Darkness of Hell". It was designed according to Koagorath's spheres—darkness, fear, terror, horror, and dark. ANd it was described his realm as the Scariest realms in oblivion as in Purple fires on ground even on barrels or as light, darkness, terror, fear and even the mortals are scared of him. His realm also have plenty of souls that you can hear the lost souls that are now Koagocath's. It also have the spawn where his famous Darkness Knights.

Artifacts
There are four artifacts total made by Koagorath which are known on the mortal plan. The famous artifacts are the Soultrapper Spear and Darkness Robe.

Urn
The Urn is the one known most powerful artifact objects known for Koagorath to keep the souls in the urn to keep him and her daedric princes and daedra army stronger. f judged worthy, its power grants the wearer invulnerability to most common magical attacks and forms of drain health.

Across Tamriel, Koagocath's urn is said to be powerful and curse object, it's that it just a normal Golden Urn but it's only have same black lighting around it. But it was later lost and forgotten until the beginning of the third era. The Urn was created during the The Elder Scrolls III: Morrowind. The Nerevarine was the first to used the urn, but it was false that it was not controlled Koagorath. The Nerevarine was not cursed. The Urn was not cursed until after 3E 427.

Later on in, it appears when the Hero of Kvatch after that quest, "No One Stole the Urn" when the Koagorath told the Hero that Lord Hakon stolled the urn, after Hakon was killed, Koagorath awards the Hero and let the keep the urn.

In when the DLC Dawnguard, it appears again when Koagorath told the Dragonborn that his urn again stolen by the Lord Harkon by Volkihar Clan. When Koagocath told the Dragonborn to tell his brother, Molag Bal that Koagorath's urn become stolen. After the quest, Koagocath awards the Dragonborn the urn.

Soultrapper Spear
The famous weapon, the Soultrapper Spear had appeared both and. It was that during the events in Morrowind, it was lightly simmuilar to the Hircine's Spear of the Hunter. But it's had a gold blade with 2 sided blades, with a Black gripping. The enchanting unique weapon that does that paralyze, Casts Soul Trap on the target for five seconds, Banish, and Turn Undead. It was used both the Hero of Kvatch and the Nerevarine. Some scholars say that the Spears was made way before Koagorath was made. In the events in Morrowind, the Nerevarine was rewarded a Soultrapper spear by Koagorath after the quest "Soultrapper". In Oblivion, the Soultrapper returns when the Hero of Kvatch was rewarded the Soultrapper by Koagorath after the quest, "The Last Soul".

Darkness Robe
One of the arotiras' artifact was the Darkness Robe or (Robe of the Dark) was a unique robe used by the both Hero of Kvatch and Champion of Darkness. The robe was cast the Soul Trap on the target for ten seconds and it will Banish the target for 25 seconds This is not a best artifact by mortals but it aleast good idea to trap the souls.

The Darkness Robe onced used by the Neravrine after the quest, "Darkness But in Hell".

Trivia

 * Koagocath is the only daedric prince that have both Molag Bal and Hermaeus Mora as his brothers.
 * Both Molag Bal and Koagocath is known as the Brothers of Destruction.
 * In and, Koagocath was one of Daedra of the House of Darkness and Terror, beside Molag Bal, Hermaeus Mora, and Vaermina.
 * Potema Septim, or the Wolf Queen summoned Koagocath to released her reign of terror.
 * High King Emeric summoned Koagocath on 2E 584, which makes Emeric and Koagocath rivals.