Iselus

Iselus El-Arde Cowen (also translated as Itherus by Sentai Filmworks, and Icelus by fan translators) is the third child of Phenel and Saraliya, and the younger brother of Risselthea and Raynesia.

As the only male direct descendant of Sergiad, he is the primary candidate to succeed his grandfather as Duke of Maihama and thus head of the Eastal League of Free Cities. Currently, his father serves as his guardian.

He was first introduced in the Log Horizon TRPG supplementary material, but made an official appearance in volume 10.

Appearance
As a young boy, Iselus has a short stature and barely reaches Isaac's waist. He typically wears a green jacket with off-white pants and boots.

Personality
Iselus is young and excitable, particularly when it comes to Adventurers. However, despite his youth, he is intelligent and observant thanks to his strict upbringing as the successor to the House of Cowen.

He is also surprisingly emotionally intelligent for his age, as seen from how he correctly deduces that his mother might have wanted to choose a different path in life from observing her body language.

Before the Catastrophe
Iselus is the child of Phenel and Saraliya, and thus the grandson of Sergiad. Because Serjiad himself has no sons, Iselus will inherit his place in the Eastal League of Free Cities, despite his young age&mdash;nearly eight years younger than Raynesia, and much younger than his eldest sister Risselthea.

Return of the Goblin King arc
Although Iselus is not seen in this arc, he was aware of the Adventurers' help in defeating the main Goblin forces and began idolizing them after that. He often pleads to travel to Akiba, where his sister took up residence following the events at the Conference of Lords and Goblin Extermination Force.

Noosphere arc
After Isaac and the Black Sword Knights are sent to Maihama to help improve relations with Eastal, Iselus quickly gains a liking towards Isaac and pursues him everywhere, to the man's annoyance. However, Isaac quickly comes to realize, after being assigned to protect him, that he was much more mature than he looked, as he was seen making plans to improve Maihama despite his young age.

The night of his birthday, his grandfather announces him as his successor as Duke of Maihama. Although power-leveled People of the Earth assassins from Minami come to slay him, he is saved by Isaac, who resolves to stay in Theldesia for his new young Earthling friend.

Collapse of the Round Table arc
In Akiba, Eins' ascension as Duke of Akiba causes political repercussions in Eastal, where many nobles fear that the Round Table Conference has went under Westelande's sphere of influence. To resolve this, Isaac quickly tells Serjiad that his Black Sword Knights stand with Maihama—partly to show sincerity, and partly because Isaac wants to keep watching over Iselus.

When Raynesia tries to win her independence from the House of Cowen, Isaac and Iselus are having another training session. While they are taking a break, Iselus recalls that when he was younger, he often saw his mother Saraliya looking up at the sky, and that he always wondered how she really wanted to live her life.

Trivia

 * Iselus shares his Japanese voice actress, Mariya Ise, with his sister Raynesia.