A.C. Eos

"Are you going to give up? I thought that you were going to keep fighting in my place? Stand up, Mega Man. You have a lot of friends who are waiting for you back on Earth... Believe in yourself... And in what you can do... ...I mean... You don't think that I'm really done for, do you? So why are you lying on the ground? You can do this... And don't forget... You're the world's greatest hero!"

- Ace telling Geo to never give up.

Arthur C. Eos (A. C. Eos), known as Shidō Akatsuki and often referred to by the nickname Ace, is one of the two deuteragonists (along with Sonia Strumm) of Mega Man Star Force 3.

Ace is a Satella Police Commandos officer that can EM Wave Changewith his Wizard, Acid, to become Acid Ace.

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'splans 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.

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!

Appearance
Ace is tall, at about 6 feet, 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.

Personality
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.

Power and Abilities
In the game, Acid Ace is a unique boss, being able to use different Battle Card attacks in succession, in addition to his own attacks. Due to the nature of his various attacks, he is capable of attacking the weakness of all non-Finalized Noise Changes, barring Rogue Noise (which has no weakness). Including his Battle Cards, Acid Ace has the biggest moveset in the Star Force Universe, and is only second to Bass.EXE in the entire Battle Network/Star Force universe. His known attacks are: Acid Ace is a highly customized and advanced EM Wave Change, designed specifically for light and mobile combat with the newest information analysis technologies.
 * Lock-On Sword: Acid Ace locks onto the player's current position, then moves to that panel and slashes it, cracking the panel. This attack cannot be blocked, and later versions have him slash two times. Sword and Break attributes.
 * Acid Blaster: Other than normal shooting device, Acid Ace use this to dispatch a variety of Battle Cards below:
 * Buzz Saw: A buzzsaw travels down the column before curving at the player's row. It can be deflected by attacking the wheel and blocking it. Sword attribute.
 * Grand Wave: A wave travels across the ground and changes rows to move towards the player.
 * Dance Fire: A flame hits all panels down the current column. Fire element.
 * Wide Wave: Fires a wave that travels down three adjacent columns. Water element.
 * Stealth Laser: Fires 3 invisibility-piercing shots down the column. Elec element.
 * Squall: A small tornado hits 8 times on one panel, removing Barriers and Auras. Wood element, Wind attribute.
 * Wing Blade: Acid Ace charges down his current column, hitting anything in his path as well as the adjacent columns. This attack can be blocked if the player is not directly in front of him. Wind and Break attributes.
 * Acid Laser: Acid Ace charges energy and fires a multi-hit laser down his column as well as the adjacent column(s).
 * Anti-Ballistic Shield: This shield is designed to protect Acid Ace's head from attacks from either side. Furthermore, it can automatically defend against any attack for which there is already pre-existing analyzer data.
 * Wing Vernier: A vernier that ejects high-density EM Wave Energy, enabling high speed movements that allow Acid to close the distance between him and his enemies for close-quarter combat. Also, because the energy is ejected at very high pressures, it works as a sharp sword that slices anyone it touches.
 * Acid-Wave Analyzer: This part comprises the whole of Acid's capabilities for information collection and analysis. It uses every piece of information before it to create an unstoppable strategy. Through Acid, it can also connect to the Satella Police database and instantly delete any virus that has been registered there.
 * Satella Police Insignia: The emblem of the Satella Police. All the Satella Police staff are required to display this symbol, which indicates that they are EM Wave crime prevention specialists.
 * Acid Blaster: An EM Wave Energy gun featuring a Hunter-VG, this weapon enables Acid to dispatch a wide variety of attacks using the same Battle Cards as Mega Man. It was originally designed with long-range attacks in mind, but Acid Ace has proven himself to be more proficient with Sword-type cards.

Trivia

 * 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)