Sieghart inadvertently caused the demise of the Highlanders and the creation of Uno. After being revitalized by the Highlanders, Sieghart accidentally left traces to their whereabouts, which Ashtaroth soon picked up on and murdered all the Highlanders, except Sieghart who was not present at the time, by his own hand. The demise of the Highlanders also led to the birth of Uno.
Uno's mission is said to be to find Sieghart, believing he can help him control his bloodlust.
Elesis is his great granddaughter. He tends to call her "Red" because of her colors. However, when they first meet at Outer Wall of Serdin, Elesis is infuriated as she claims Sieghart is disrespecting the Sieghart Family for claiming to be the great Gladiator 600 years ago. Her dislike for him dies down at The Wyrm's Maw.
Sieghart tends to be bossy and thinks these "tykes" are immature and unworthy to be a part of the Chase themselves.
Sieghart seems to retain a "cool" personality. This is supported on many of his poses (especially Gladiator seeing how he wields his sword in reverse), some of his quotes, and being very inhostle to the Chase while responding in a seemingly dignified manner.
However, Sieghart also has a big ego. This is evidenced with the majority of his quotes, often defining himself as a "legend."
Contrary to popular belief, Sieghart did not disappear at Forgotten City, and was not nearly killed by Kaze'aze. Naver Blog posted a picture of Dio attacking and putting Sieghart in his near-death state 600 years ago. However, the image was meant to promote the Sudden Death PVP Mode and any actual relation to the storyline is unknown.
Ironically, Sieghart uses dark energy via Rage even though he fights against the forces of darkness. Interestingly, as a Prime Knight, Sieghart appears more insane, similar to the possessed Lass and Iblis, suggesting that he has established control over such dark energies without being possessed by such.
Sieghart's immortality is proven by Mari's fatal explosion attack, in which, he survived. This piqued Mari's interest upon him from thereon.
In the Manhwa, it is revealed that Sieghart had a brother named Luke, and a wife name Julia. When he went to the war, he thought his brother dead, and he became immortal. He returned to his home after the war, only to find that Julia had remarried Luke. Glad for their happiness, he left. He also feels a special attachment to Elesis due to her striking resemblance to Julia.
Sieghart does not like to train nor exert himself. However, it seems he is willing to do things he doesn't like in order to fulfill his duty, as seen in his third job advancement where he mentions himself "training."
Sieghart's Rage Mode was based on Elsword's "Awakening Mode", where the characters engage a form that provides a colored aura and increases their attack power.
Although Sieghart is the oldest character, Kumi claims to be 732 years old, which is 132 years older than Sieghart. Therefore, Sieghart is the second oldest character, but the first oldest playable character.
Sieghart is the oldest human character in the Grand Chase, only due to his immortality. Were it not for that, Ronan would be the oldest human character.
Similarly to Jin, each of Sieghart's jobs follows a pattern from 1st skill to 3rd skill.
1st skill consists of a bunch of normal slashes that move Sieghart forward. It also brings the opponent into the air in certain conditions with the exception of Warlord; Gladiator needs level 2 Iron Crusher, Duelist needs the third motion of Rule Break, and Prime Knight needs the JF for Highlander Assault.
2nd skill is a melee attack using up a great amount of dark energy. They also lift the opponent into the air, though again Prime Knight needs Soul Edge's JF.
3rd skill is a massive attack that unleashes powerful slashes and shockwaves.
Sieghart is the only character whom is called by the last name instead of the first.
Like Arme, Ronan, Lass, Dio, Zero, Ley, and Rufus, despite the fact that darkness is shown in this game as evil, Sieghart's powers are fueled by darkness and he can safely wield it without giving in to its influences nor using it for antagonism. Though the dark power can occasionally manifest in him physically through his deranged and intimidating looks in battle, he has never misused it so far.
Sieghart, along with Amy and Mari, are the only characters to have their own custom expressions.
In Sieghart's case, his Leap is the only thing for him that causes players that he jumps on to have an expression.
Currently, he is the only character that actually has voiced a curse word: "Damn!".
It is possible that Sieghart is a Silver Knight, as he showed concern to King Guang in King Guang's Fen, though this was never confirmed. However, since his appearance was removed from there, his affliction with the Silver Knights seems highly unlikely.
The Sword Master's info states that he was once the Master of a Sword, this fact was only proven when his fourth job class Prime Knight was released.
With the exception of Gladiator, Sieghart has Dual Wield properties.
Excluding Prime Knight, each of Sieghart's jobs have at least one skill that has the word Punisher (or similar) in it. (Gladiator: Grinding Punisher, Warlord: Punishing Combo, Duelist: Dread Punisher)
Without the use of his Skill Tree, he doesn't have a Berserk function unlike his great granddaughter, Elesis. It is even stranger that his berserk function is also weaker.
Sieghart and Elesis share similar job concepts. This is most likely due to the fact that they are of the same bloodline.