This article requires cleanup.
You can help MMKB by improving it.

Arthur C. Eos (A. C. Eos), or Ace as he’s usually called, known as Shidou Akatsuki (暁シドウ Akatsuki Shidō) in Japan, is a character introduced in Mega Man Star Force 3. Ace is a Satella Police Commandos officer that can EM Wave Change with his Wizard, Acid, to become Acid Ace under Project TC as No. 001. He is the creator of the Hunter-VG, which allows Wizards to materialize. Due to Acid being a man-made Wizard and not a natural EM Being, the EM Wave Change puts a tremendous strain on Ace's body. He used to be in a relationship with Queen Tia.


Ace is tall, at about 186 cm (around 6'1"), though he is somewhat thin. He has dark-blue hair that goes down to his neck. His ensemble features a simple black jumpsuit similar to one of a pilot, with an attached metal belt circling the waist. Over this he dons a white jacket bearing the Satella Police emblem, with a metallic enforcement plate acting as a collar. He also wears white boots of the same materials. He wears two gray gloves with yellow steel lines running over the back of the gloves. A red visor is stuck into the collar of his suit, though it is never seen used in the game.


He often shows a cool attitude to everything he's working with. On the battlefield, he's a decisive, brave person, doesn't hesitate, and ready to take the lead against the enemy forces, sacrifices even. This gave him the leadership of the Project-TC, other than the main elite commander of the Satella Police. However, as time progress through the game events, he eventually exposes his spontaneous and optimism side, especially to his closest friends. Ace, for short, is very active in this, even when it comes to situations which require seriousness, such as when he over-enjoying the Mega Snack like a kid. This probably what made Tia fall in love with Ace, as well as everyone's feelings toward him. This trait once again was never seen in his EM Wave Changed form however, known as Acid Ace, the assertive and valiant which brings peace to this world of technology.

After trying a Mega Snack, A.C. Eos becomes very fond of them. He is seen throughout the game munching on one or several whenever he has time to do so, to the point that it worries Acid. They can be found under his desk, and woman who runs the snack shop at Geo's school informs him that Ace bought them all.

Game History

Mega Man Star Force 3

Geo Stelar first meets Ace at Echo Ridge Elementary where he asks Geo to enter a tournament being held at Spica Mall. Geo is late to the tournament that Ace won in a couple of seconds.

During the events of the game, A.C. Eos teams up with Mega Man and his friends to attempt to thwart Dealer's plans for world conquest. He provides Geo with the Ace Program or Joker Program (depending on game version) to allow Mega Man to control the influences of Noise. He also leads a team of Satella Commandos with wave change capabilities, comprised of Geo, Bud Bison, and Sonia Strumm. Later in the game, it is hinted and then completely revealed that he used to be a member of Dealer before leaving and joining the Satella Police. In the past, it seems that he used to have a romantic relationship with Queen Tia.

During the Dealer attack on WAZA, he defends the base and then fights against Queen Virgo. Virgo gains the upper hand early, but Ace turns the battle against her. However, his Wave Change is canceled because of the strain on his body. He then requests that Geo defeat Virgo, which he does. Ace supposedly dies when Dread Joker blows up in the Dealer hideout, but manages to tell Tia that he loves her before he disappears.

Acid, Tia and Dr. Goodall tending to Ace at the hospital in the Star Force 3 credits.

A message gets sent to Geo from Ace, much to his surprise, and the message was programmed to automatically be sent to his friends and colleagues, as well as the Satella Police members. Ace tells Geo to not give up hope, and gives him the last battle card up his sleeve, Dread Lazer or Wing Blade.

Toward the end, when Crimson Dragon knocks Geo down and starts giving up on the fight, he sees Ace before him, asking why he has given up, when he is supposed to be taking his place in the fight. He tells him to not give up, because he is the hero of justice, after all!

Fans are skeptical because when the credits roll, an image of Ace can be seen in a hospital, being taken care of by Dr. Goodall and Queen Tia, suggesting they found data frags of him and reassembled him and Acid like they did with Luna. However, in the Mega Man Star Force Official Complete Works artbook, Yamashita, leader of the scenario team, implies that the image might be a representation of someone's desperate wish, and that Ace may not have survived at all, and they left it for the player to decide.[1] However, there is a strong evidence in favor of his survival, since his brotherband was not cut from Geo (Brotherbands will exist until one of the people dies, which was what Geo used as a proof of Luna's survival earlier when she was destroyed by Joker).[2]


Language Name Reference
English Arthur C. Eos Dr. Goodall often refers to A.C. Eos as Arthur, implying that to be his first name. In Greek mythology, Eos (Greek Ἠώς, or Ἕως "dawn") is the Titan goddess of the dawn.A.C. Eos' initials spell the word "Ace", which is often used as his nickname, and is a direct reference to the playing card of the same name. Ace is also a term used for someone of great skill in things such as sports or shooting.
Japanese Akatsuki Shidō

Akatsuki (暁) means "dawn".
Shidō can mean guidance(指導) or chivalry(士道).



  1. These images came together easily because I wanted "Star Force 3" to have a happy ending, where everyone has a smile on their face. I can't say for sure what happened to Ace, though. Did he survive? The image with him laughing and chatting in a hospital bed may be reality, or it may just be a representation of someone's desperate wish. I will leave that up to the player's imagination. (Yamashita, Scenario Team Lead) - Mega Man Star Force Official Complete Works, page 91.
  2. (The reason Prez's data and our shared Purpose hasn't disappeared is that she is still alive... And because our bond with her is still strong...!) - Geo, Mega Man Star Force 3