Incest

To Do This article mentions specific incestuous relations of House Arana, which are currently being redone.

Incest is defined as a relationship between two persons commonly regarded as too closely related to marry.

Effects

Unlike incest on Earth, inbreeding on Nirn does not appear to have the same congenital consequences. Deformities can occasionally occur, though what is seen more often is a scarring of the mind. Prolonged incestuous unions increase proclivity to madness and cruelty among the children of such unions, though such mental states are still rarer than incestuous congenital defects are on Earth.

Such mental effects can be seen among the orcs of orcish strongholds, known for their viciousness in battle and unrelenting brutality to their enemies, and the Ayleids of the Ayleid Empire, known for their cruel, inhumane, and detached behaviour when dealing with non-Ayleids, and even some Ayelid commoners.

A way of visualising the effects of inbreeding would be 'turning things up to eleven'. For example, the inbred Ayleids are not any more evil than a non-inbred Altmer, but they have a greater proclivity to rage and cruelty. Where a servant accidentally cutting a noble with a butter knife might have angered an Altmer noble, sending the servant to the stocks or sacking him, an Ayleid noble might have had one of the servant's fingers removed. This kind of extreme behaviour is known to occasionally go both ways, where some people go on to do great things while others descend into cruelty and tyranny. Such extreme behaviour was seen in the War of the Shrine of 1E 239 where King Anumaril Arana of Abagarlas declared war on Delodiil over disparaging comments made about Anumaril's religious shrine. A monarch who was not so deeply inbred might have responded differently, but Anumaril prepared for war. The converse side of incest is also seen in King Anumaril's brilliance, as he created the Staff of Towers and was among the most powerful and intelligent sorcerers of his time.

Incest in Tamriel

The main religions practiced in Tamriel consider incest to be a vile sin. However, in Tamriel incest is only applied if parent lays with child, or sibling with sibling, and the children of such unions are considered abominations. In marriage customs, it is acceptable and in fact quite common among the nobility for cousins to wed. 

The views regarding marriages between an uncle and a niece (or an aunt to a nephew) might differ between Altmeri-rooted religions and other religions.

Incest in Orc Strongholds

The orcs of orcish strongholds across Tamriel practice a much higher degree of inbreeding than the other cultures on the continent. Following the Code of Malacath, the only orc permitted to mate in any stronghold is the chief, making sibling marriages within strongholds commonplace. Equally common is marrying the daughters of chiefs from other strongholds, which over centuries develops into pure cousin marriages.

Incest in the Summerset Archipelago

The only exception to condemnation of incest in the Summerset Archipelago is when it occurs in House Arana. The Altmer accepted the rule of Aerel I Arana following his Invasion, despite the fact that he was in an incestuous marriage with his sister Alyssare. The High Aldarch personally anointed the new king, and Aerel remained closely allied with the clergy during his reign, but the religion neither denounced nor endorsed Aerel's marriage.

Some time after Aerel I Arana's death, the Church Uprising began against the rule of Aerel's son, Daethen I. The High Aldarch sent Daethen a denunciation, addressing him as "King Abomination"; pious lords and commoners, who had once respected Daethen, turned against him. The uprising lasted the remainder of Daethen's reign and continued throughout the reign of King Anumaril I Arana. Peace between the Church and the Crown was eventually reached during the reign of Viseriel I Arana with the Principle of Exceptionalism, which permitted incestuous marriages for Aranas, as the gods had made Ayleids differently from the Altmer. It was made an official tenet of the faith by High Aldarch X.

The Aranas continued their incestuous marriages from the reign of King Viseriel I onwards. King Viseriel I married his first cousin Firen Arana. Viseriel then married his eldest daughter Elaerel to his son Lucerel. Viseriel further married his second son Aenyril to his aunt Calastil Arana. Such incestuous marriages continued down the Arana line, some say leading to a proclivity for madness among those of Arana blood.

Altmeri society tolerated incest only among the Aranas, though other Houses of Ayleid descent were known to occasionally practice it, such as the Errinornes of Skywatch.

Incest in the Ayleid Empire

In the Ayleid Empire, it was custom among the high nobility to marry brother to sister, or, if that was not possible, an uncle to a niece, or an aunt to a nephew.