This Player, Jack, is property of FedeTkd.


Lone Ronin



Personal Info
Real Name Jack Mars
Kanji ジャック マルス
Romaji Marusu, Jakku
Birthday July 9th , 2006
Age 18
Gender Male
Height 1,80cm
Weight 70kg
Player Profile
Display Name Jack
Kanji (Display) ジャック
Romaji (Display) Jakku
Epithet "Lone Ronin"
Occupation Mercenary (former)
Solo Player (former)
Player Killer Killer
Guild Member
Affiliation The Supreme Legion (Former)
Knights of the Blood(NA)
Base of Operations None
Status Alive
Voice Actor Takanori Hoshino
Appears In Sword Art Online: New Aincrad

There will only be one King! And that one will be me!
~ Jack

Jack is a solo player of New ALfheim Online. He is one of the tritagonists in Sword Art Online: New Aincrad.


New ALfheim Online Avatar

Jack is a tall man, with purple eyes, fair skin, and spiked blonde hair, with two much longer pieces in front of his ears that hang further down the rest of his hair. His avatar is an imp.

His outfit consists of a white long coat with violet insides and matching boots. He uses dark grey trousers and same colored forearms protectors. Inside of his coat, he has a white t-shirt, and he carries a pendant around his neck. He wears a metal belt on his waist, over his coat, where he generally carries his sheathed katana.


Jack is a confident and powerful player who deeply believes that with his power he can overcome any obstacle or challenge given. He is arrogant, somewhat boastful, of his skill as a fighter and is always searching for a greater challenge to gain strength and test his true limits.

He has a very strong pride as a warrior and believes that dueling is a clash between souls. By analyzing the fighting style of his opponent, he can learn many things about him and figure out the personality of the person he's fighting against. He also refuses to attack abuse or mistreat the weak or the defenseless.

Jack holds the belief that power’s the only thing that ever mattered in the history of humanity. The weak have been always forced to serve the powerful. Jack wants to keep on training and fighting so that he can one day defeat Hao and become King of Aincrad.

He can be emotional, hot-headed, occasionally violent. He never feels more alive than during a fight with his life in the line. However, he starts showing his caring for his guildmates as the series progresses and he matures, becoming close friends with his rival Galant and with Kana.


He was born in England, but when he was still young, his parents moved to Japan, and he lived all his life there. He joined New ALO sometime between 2025 or 2026.

In the game, he was a very loyal Imp soldier. Once The Supreme Legion appeared, Jack started working as a mercenary and was the contact between the Legions and the Imp army. This ended once a rebel faction of the Imp Army attacked Hao's guild. Hao sent them a message of truce by Jack, and the Imps reluctantly accepted. However, in the meeting, the Legions slaughtered the leaders later they faced the Imp army. The battle ended in an absolute victory for the Legions. Jack faced Hao in battle, but he couldn't defeat him. He escaped from the battlefield, swearing vengeance.

Jack became a renegade for the Imps and a traitor for the Legions. Since then, he wondered in Aincrad searching for worthy opponents to become the strongest player and win the Great Aincrad War and become the King of Aincrad.



Jack and Yakuza became rivals since they first crossed blades. and are searching to defeat one another.


Jack sees Galant as a powerful rival. As he's a player that stands in his way to become the strongest, Jack wants to face Galant someday in a full fight. After spending time together, Jack and Galant have developed a strong friendship and respect for each other.


When Jack joined The Supreme Legion, he had a friendly relationship with Hao. This lasted until Hao's legions slaughtered his own race. After this Jack just saw Hao as an enemy to be defeated.


Kana and Jack quickly bonded once Jack joined their guild. They have a friendly relationship with each other.


Zar (as Lyd) and Jack had a brief fight to test the former's prowess in battle. He proved to be quite skilled, almost matching Jack, but he nevertheless, defeated the Spriggan. However, Jack promised to give Lyd a rematch.

Jack was notably angry when he learned that Lyd was actually Zar.


Jack is an incredibly skilled player. He is unmatched in the use of katana, having mastered the use of his personal odachi Yahaza. He fights with iaijutsu-style, delivering swift and gruesome strikes and death to any and all opposition. He has fast, swift and strong draw, and extremely deadly. He can make several slashes with the sword before he sheaths it back it back again.

When he uses it to his full potential, he can slash meters beyond the actual length of his sword. He also has shown ability wielding Yahaza with either hand but favors his right over his left. Jack also uses his scabbard as a weapon, either to block the strikes of another player or using it as a club.

On rare occasions, he wields his odachi with both hands, switching to a style more influenced by kenjutsu. Though this style is not as fast as his sword-draw, he compensates this by with stronger sword slashes and parries. With this, he takes a more solid stance, holding his blade in front of him, ready to strike with deadly intent. This style also allows Jack better defense that his other, but he still favors a more aggressive style, using the reach of his sword as an advantage against his enemies.

He has also shown skill darkness magic, his race's specialty. He generally ignites his weapon with violet fire while attacking, what greatly increases the power of his attacks. Jack's signature spell is "Dark Blade", which creates katanas or wakizashis made of Dark Magic. He generally uses these weapons to support his katana-wielding. Jack has also shown skill in hand to hand combat and possesses Martial Sword Skills. He has proven able to fight several members of The Band of the Nine and match Galant's and Hao's prowess in a fight.

These combined skills make him a fearsome warrior and one of the best katana wielders in New ALO.

New Alfheim Online

  • Level: 100
  • HP: 20000
  • MP:1000

Main Equipment


Nihontō Sword Draw Sprint Battle Healing Parry
990 / 1000
Searching Acrobatics Detection Tracking Light Metal Equipment
Extended Wight Limit Martial Arts

Martial Arts Skills

  • Ryu-Ken
  • Spell Blast - Interception of a spell using a Sword Skill.
  • Skill Connect - Chaining multiple one-handed weapon Sword Skills.

Music Themes

Jack's Theme

Jack's Theme


  • Jack is the first katana wielder on the Wikia that doesn't use traditional japanese clothes.
  • Mars comes from the god of war in Roman Mythology. Mars was the roman equivalent of Ares, greek god of war.
  • Jack's battojutsu-style is quite similar to Yamato's own "Dark Slayer" fighting style, but unlike the latter, Jack ocasionally uses his sword with both hands.
  • Jack's fighting style is based on Ishida Mitsunari's and Uesugi Kenshin. It's also influenced by Kisara Tendo's Tendo Drawing Sword Style.
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