Hollow

Hollow, know as Empty (エンプティー) in Japan, is an EM being from Mega Man Star Force 2. Hollow is Dr. Vega's assistant, a materialized being composed completely from Matter Waves. He is empty inside, and was aptly named for this trait.

Mega Man Star Force 2
Hollow is actually an imitation of Dr. Vega's dead lover, Altair (Hiko in the Japanese version). After his death, Vega created a method of making EM Waves solid in the hope that she could recreate Altair, but unfortunately, Hollow had none of the deceased Altair's memories, and would remain without them. Grief-stricken from her loss, Vega began looking into the ancient powers of the Murian civilization, possibly in hope of reviving Altair, and modified the copied form to be better oriented for combat, creating Hollow.

After Geo's friends were scattered throughout the world, Hollow finds Harp Note before Geo does, and manages to convince her to join Vega, informing her that Geo would come to no harm as a result (however, while he was being honest, he did not mention that there was the need to extract the OOPArt from him first). Hollow also grants Rogue the power of the Indie Proof (including the Mu Rejection barrier), and proceeds to attack Wilshire Hills with an army of Murians. When Mega Man shows up there, Hollow sics the newly powered Rogue on him as he makes his escape.

After Mega Man gets Harp Note back to his side, the both of them track him to the deepest part of the Bermuda Labyrinth, where the continent of Mu was sealed (Vega's floating base had drifted close in its search for it). After Mega Man takes down Hollow, Rogue shows up and fights him, and shortly after, Hyde takes advantage of Mega Man's weakened state and seizes the OOPArt that Omega-Xis had swallowed.

Prior to the final battle on Mu, Hollow appears again, and is also interrupted by Rogue. In an attempt to hinder Rogue and Mega Man, Hollow uses the Kamikakushi to attempt to trap the three of them in an alternate dimension, but Rogue throws Mega Man out, telling him to defeat Le Mu, whilst Rogue and Hollow duke it out.

After Le Mu's defeat, Hollow abandons his fight with Rogue, and appears to ensure that Vega's plan goes unhindered, and Mega Man attacks, exposing the form of Altair from beneath Hollow's robes, prompting the revelation of Hollow's history. When Le Mu begins to go out of control, Hollow sacrifices himself to protect Vega from the sudden onslaught. As Hollow is deleted, he thanks Vega for once again giving him life while also apologizing that he could not fulfill her wish. He prays for Altair to speak to Vega, and he actually does so, telling her to live a long and happy life.

Shooting Star Rockman Tribe
Due to the lack of time as the anime was canceled and had to be wrapped up quickly, Hollow's backstory was not explained. Also, Hollow is almost impossible to defeat if he's hooked up to an energy source. If not, he doesn't have a chance. Hollow is defeated at the hands of Geo Stelar when he turns into Mega Man with the help of Omega-Xis using the three OOPArts allowing him to become Tribe King. Still as in the game his loyalty to Vega remains intact as well as how Vega has him very well estimated, as he was healed by the two OOPArts given to him, as well as when he met his end Vega was overall shocked by his death, implying that he may have followed his previous role.

Abilities
Hollow starts the battle with six specially designated panels. These are where he summons his viruses from, and if the panels are removed, no viruses will be summoned. Later versions can restore removed panels.
 * Hollow Barrier : After a set time after moving, Hollow will generate a barrier around him. This can be pierced by Breaking attacks.
 * Summon Virus: Hollow can summon a virus on one of the special panels. If currently in Tribe On mode, the virus summoned will be the element the Tribe is weak to.
 * Dance Fire: A BubbaDance virus will be summoned, performing its flamethrower at the player.
 * Chain Bubble: A StreamCancro virus will be summoned, creating bubbles at the player.
 * Stealth Laser: A Stealth virus will be summoned, firing three Invisibility-piercing shots at the player.
 * Squall: A Storm virus will be summoned, unleashing a wood tornado at the player. Removes Barriers and Auras.


 * Magic Thunder: Hollow will summon lightning bolts that will strike down on the row in front and the player's row. The black version will also rewind to hit both rows in backwards.


 * Thunder Bazooka: Hollow will fire a lightning blast down the row. The black version of this will spread to adjacent panels.


 * Invulnerability: (Anime only) Hollow, consisting of a living Utagai Area, is invulnerable to almost all forms of attack; however, this requires him to be area-bound to his current power source. This limit is removed when he imbibes the power of the Saurian and Ninja OOPArts.

Trivia

 * Hollow is the world's first Matter Wave (mass-produced Matter Waves are all founded in Dr. Vega's research from when she was creating him), and functionally, the first ever Wizard.
 * Hollow shares several traits with MagicMan.EXE. They have the same attack pattern (summoning viruses accompanied by a straight-lined attack), both have wizard-like apppearances, and he shares Yahoot's position as the main villain's right-hand man.
 * His anime version shares a similar trait to the game version of ElecMan.EXE. Both are invulnerable when hooked to a power source, ElecMan.EXE being connected to electricity that will heal him every attack, and Hollow being invulnerable.