Sheidheda

Sheidheda (Dark Commander in Trigedasleng) is a recurring character in the sixth season. He is portrayed by Dakota Daulby and debuts in "Memento Mori".

He was a Commander, given the title Sheidheda because of his dark history. He killed his own Flamekeeper and has been using the Flame to convince new Commanders to turn evil and to kill people, including their own teachers. To help newly-chosen Commanders from being controlled by Sheidheda, the Flamekeepers came up with the "Separation Ritual", during which the Commander calls upon the past Commanders to help stop Sheidheda.

Early Life
Sheidheda was born a Nightblood and eventually became a Commander of the Grounders. Instead of following the teachings of his Flamekeeper, he felt like the Flamekeeper was trying to control him. He eventually became impatient and killed his own Flamekeeper. He ultimately killed three Flamekeepers before being killed himself by his fourth.

Throughout the Series
In The Children of Gabriel, Madi mentions to Gaia that while listening to the past commanders, she has been hearing a commander who scares her. Gaia reveals that it is Sheidheda - the Dark Commander and asks Madi to avoid him.
 * -|Season Six=

In Memento Mori, Madi is communing with the other commanders including Sheidheda. Gaia mentions to Josephine (pretending to be Clarke) that Sheidheda is getting too strong and they need to perform the Separation Ritual to stop him. Josie ignores Gaia's advice and wakes Madi up abruptly. After that, the Dark Commander starts revealing himself to Madi whenever she looks in the mirrors. After realizing what's going on, Gaia tells Madi that they must perform the Separation Ritual right away in order to call upon the other commanders to stop Sheidheda.

During the ritual, Madi finds herself in a room with no one but Sheidheda. Sheidheda tells Madi that Gaia is lying to her in order to restrict her. He tells her that his own teacher used to control him too so, he killed him. He urges Madi to kill Gaia. Madi refuses and wakes up. Later on, after learning that Clarke is dead, Sheidheda convinces Madi that Gaia is to blame for Clarke's death. He asks Madi to kill Gaia but Madi banishes her instead. Taking advantage of Madi's anger and grief, Sheidheda agrees to help guide Madi in her quest to kill the Primes.

In The Old Man and the Anomaly, Madi sees Sheidheda as she discusses killing the Primes with her friends and effectively committing genocide upon Sanctum. When they refuse to help her, Madi enacts her plan on her own under Sheidheda's influence.

In Matryoshka, Sheidheda continues to influence Madi to madness to the point that Gaia suggests killing Madi to prevent Sheidheda from being loosed upon the world which would make them long for the days of Blodreina. As the others try to get answers from Madi, Sheidheda orders her to tell them nothing. Raven Reyes realizes that Sheidheda managed to isolate the spirits of the other Commanders, somehow manipulating the AI inside the Flame to do it. Raven suggests that this means that the code from the minds of the Commanders can be deleted and they can possibly get rid of Sheidheda for good. Raven orders Gaia to go get get Becca's book to see if her theory is correct.

Personality
He can be imagined as a demon, prompting his successors to kill other people.

Physical Appearance
He primarly wears a hood underneath of it to hide his facial scars. He only has an eye on the right side of his face where as on the left side it's just all skin over what used to be his eyelid. He's an pale blond man who keep his hair in a manbun.

Killed Victims

 * Three Flamekeepers

Notes and Trivia

 * He was a Nightblood.
 * His first teacher chained him to a wall, which made him kill that teacher.
 * He was a feared ruler of Polis during his lifetime as he wants Madi to kill others such as Gaia since his victim record includes his flamekeepers/teachers.
 * According to Gaia, if he is able to successfully use Madi to continue his reign of terror, it will be much worse than even Blodreina.
 * He is the first male commander shown in the series.
 * He was called the "Dark Commander".