Maestro

Physical appearance, personality, relationships, gallery
Maestro (マエストロ (総指揮者), Maesutoro) is a mysterious character who is first introduced in the manga adaptation of Fuga: Melodies of Steel and makes his first appearance in the main series with Fuga: Melodies of Steel 2. He will have a major role in Fuga: Melodies of Steel 3.
Maestro is a man of uncertain race and with unknown goals who resides in the Deep Depths. He offers advice to Malt every time he dies.
History
The "Maestro", something he refers to himself as, is an eccentrically dressed being who has full knowledge of the events that had taken place in the Free Lands of Gasco, specifically the war against the Berman Empire. He watches the timeline's events on multiple digital monitors and appears to possess knowledge of currently unknown events that have occurred, both in the present and future. Due to this ability, he has some trouble comprehending the linear perception of time of most of Earth's inhabitants.
Fuga: Melodies of Steel 2
Maestro meets Malt after the disastrous rematch between the Tarascus and the rogue Taranis in Pharaoh. Because Malt and his friends hesitated to harm those who had been brainwashed by Jihl, this allowed the latter to sacrifice Mei to activate the Soul Cannon and obliterate the Tarascus with it. Ending up in the Deep Depths, a strange location with flowing lines, hexagons, and a glowing golden Juno, Malt wondered what had happened to Mei and his friends while on the verge of despair, when Maestro startles him.
Impressed by Malt somehow reaching his location and comparing his newfound temporal abilities to Jeanne's, Maestro gives Malt a little advice to avoid the terrible fate he just suffered and wishes him victory, while also warning him that the place they'd met would become his new reality if he failed. Once Malt returns to right before the fight, his desire to save Mei and his friends gives him and the other children the resolve to fight their old tank, which leads to Mei being saved from the Soul Cannon and reuniting with her brother.
They both meet again some time after the Taranis transforms into the Exo-Taranis, when Malt's hatred of Jihl due to Hanna's death causes him a severe lapse of judgement that drives him to argue with his friends, leaves the tank unable to move due to enemy artillery fire and gets him killed by the Hax AI when he decides to use him as Soul Cannon ammo. While in his realm, Maestro berates Malt for him choosing to keep pursuit of the Belenos over defending the village Jihl's Verschlinger attacked, and also tells him he should have a better choice of last words, as he was practically begging to get himself killed with his actions. After also telling him that no life is worth throwing away so easily, he remarks that Malt will probably forget their conversation before time reverses to when Jihl created the Geist. As Malt is left too shaken to argue with his friends, it allows them to focus on destroying the monstrous helicopter before it can harm the Exo-Taranis.
Malt meets the Maestro a third time after Cayenne Riesling obliterates the Taranis with a brainwashed Vanilla and the fully-powered Belenos, in the depths of Mastiff. Once Malt returned to the Deep Depths after going through a dream version of Petit Mona, he was startled by the entity once again. Upon realizing he'd never properly introduced himself in their past encounters, the Maestro promptly did so. He told him that similar to an orchestra's conductor, he conducted symphonies (stories) of hope and despair. Confused by his words and musings, Malt asked him who and where he was. The Maestro explained to him that the tragic end the children had just endured was actually a vision of a potential future. As his explanation had left Malt even more confused, the Maestro clarified that the future was full of endless possibilities, and thus, Malt could choose an entirely new future, either full of hope or with even worse despair and tragedy down the line. All that mattered was if Malt was brave enough to try again. Malt showed his resolve to bring upon a better future. The Maestro warned that he could still end up with a darker future, but seeing that he and his friends had gone quite far to that point, he spurred Malt to take the chance. He then told Malt to speak with his friends, so the words in their hearts would give Malt the answers he sought.
With little warning, Malt was sent to a manifestation of the Taranis, floating in a sea of blue clouds and flying lights. Inside were the other children, on the throes of despair due to their brush with death. One by one, Malt reinvigorated their spirits, including those of Hanna and Jihl. Once he finished talking with Jihl, Malt returned to the Deep Depths. Maestro, amused by Malt's actions, informed him that he'd done a few alterations to the past to ensure that his story and the Taranis' would continue. Before Malt could inquire more in his words, the Maestro gave him a final advice, which was also a warning: each of Malt's decisions could bring upon hope or despair, and it was up to him to choose between either. Either way, Maestro was sure he and Malt would meet again.
The alteration Maestro did was simple: He removed Cayenne's Nono geas in Vanilla, saving her life in the process. As the Taranis was never sabotaged, Hax engaged the tank's shields and blocked the Belenos' attack, which allowed her to survive the battle and the collapse of Altar 4, which buried the tank under rubble.