Personality & Character
Slaine is shown to be very friendly with Princess Asseylum Vers Allusia, being completely loyal to her. When presented with the possibility of her being alive, he boldly went after her alone. His loyalty to the her can be further attested by the fact that even when he was being tortured, he would still not reveal that she was alive.
He is more than willing to fight in order to protect Princess Asseylum, and yet he saved Count Saazbaum's life despite the fact that he is an enemy of Princess Asseylum, showing a lack of control of his emotions; however, this is likely due to how Slaine sympathies the count for the loss of his fiancée after hearing his story and seeing a recording of Orlane's demise. Most Martians have viewed him with contempt whereas others like Count Saazbaum and the soldier who saved his life have not.
Skills & Abilities
Slaine is shown to be a capable aircraft pilot, being able to handle fast and tricky maneuvers. (AZ: "Beyond the Horizon", "The Children's Echelon") He is also able to pilot the Tharsis due to the Aldnoah activation right he unknowingly possesses. After 19 months, Slaine is shown to be particularly skilled in piloting Tharsis, being able to fight off Inaho. (AZ2: "Toll for the Brave")
The son of Dr. Troyard, a researcher of Aldnoah, Slaine crash landed in a rocket on Mars. At the time, he had a large amount of hyper-oxygenated fluid in his lungs for Liquid breathing, and coughed violently in an attempt to remove it. A young Asseylum who happened to be nearby at the time assisted him with reverse mouth to mouth resuscitation (sucking liquid out, instead of breathing air in).
When Dr. Troyard died on Vers, those who had known him now thought of Slaine as a nuisance. Princess Asseylum attended his father's funeral and comforted him afterwards. During a conversation between the two, Slaine had told Asseylum about his father and how back on Earth he was enveloped all the time in his research. Afterwards, Saazbaum asks Count Cruhteo to take custody and watch over Slaine.
After Vers had declared war on Earth, Slaine was ordered by Count Cruhteo to pilot a Sky Carrier and carry Sir Trillram's Nilokeras. With great surprise, Slaine spotted the Princess alive and well when the Kataphrakt was defeated. Shortly after, Slaine learned from a frustrated Trillram that the Princess's assassination was orchestrated by a group of Orbital Knights and, out of a fit of rage, stole Trillram's gun and killed him on the spot.
After finding out Princess Asseylum was alive, he tracked her down using his only lead, an orange KG-6 Sleipnir, which was piloted by Inaho. Using a Sky Carrier he stole from Castle Cruhteo, he flew towards Tanegashima where it was last sighted. After locating it, he arrived in the nick of time and stopped one of the Hellas' fists from finishing off Inaho Kaizuka and his ship. Assisting with Inaho's fight against the Kataphrakt, they were able to defeat it with their combined skills. However, Inaho later shot him down out of distrust and mis-communication on both sides. (AZ: "The Boys of Earth")
Recaptured by the Count Cruhteo, Slaine was tortured, but did not reveal anything. Count Saazbaum tried to dissuade Cruhteo from killing Slaine on several occasions and when it seemed Cruhteo was about to kill Slaine for sure, Saazbaum decided to launch a sneak attack on Castle Cruhteo with the Dioscuria in an attempt to save Slaine. Before Saazbaum arrived however, Count Cruhteo figured out from Slaine's words and his men's reports on Tanegashima that the Princess was still alive and Slaine acted alone out of loyalty to protect the Princess. Assured of his loyalty, Cruhteo ordered his men to tend to Slaine's injuries and to contact the UE HQ for cooperation in finding the Princess. However, Count Saazbaum shortly arrived in his Dioscuria and quickly killed Cruhteo after the latter figured out Saazbaum was behind the assassination plot. Saazbaum subsequently took Slaine back to his own Landing Castle. (AZ: "Then and Now")
After Slaine woke up in Saazbaum's Landing Castle, the latter explained he saved him because he owed Slaine's father a debt for saving his own life during Heavens Fall. Saazbaum also explained to Slaine why he attempted to assassinate Princess Asseylum and his motivations for starting the war. Shortly before attacking the UFE HQ, Saazbaum gave Slaine the option to join his forces or flee to Earth. In return for efforts of saving Count Saazbaum and Princess Asseylum during the assault on UFE HQ, he was given the title of Sir, got his own servant, Harklight and inherited Count Cruhteo's Tharsis. (AZ: "Childhood's End", "This Side of Paradise")
Count Saazbaum later adopted him as his son and heir; however, soon afterwards, Count Saazbaum was killed by a rain of bullets Slaine intended as a trap for Inaho, and thus Slaine was promoted to an Orbital Knight, holding the full title of Count Slaine Saazbaum Troyard. (AZ2: "Toll for the Brave")
After Empress Asseylums' announcement that the Imperial Family wishes to make peace between the Vers Empire and Earth, Slaine decides to disregard her command to cease all hostilities. Although he is surprised that she had the strength and will to make the decisions that she made. Shortly thereafter Slaine meets up with Princess Lemrina Vers Envers, and she talks about continuing Slaine's dream since she isn't going anywhere. Along the way to the hangar, Slaine remarks how he's seen a great many things; meaning the future, both the good and bad. Thinking that he knew everything even though only the immediate future can be seen. Finally he goes on to say that even though certain things went as he foresaw them to, he had failed to see what was truly important. After arriving at the hangar, he announces that everyone on the Moon Base and those who are deployed, be clear of the base within 10 minutes. He apologizes to Princess Lemrina for all he had done, and wishes her good health. He leaves for the command center deciding to let himself die with the self-destruct of the base. During the evacuation Sir Harklight decides to make a selfish decision and continue to fight along with the Stygis Squad. Motivated by seeing his soldiers fight again, Slaine joins the fight, and faces off with Inaho Kaizuka for the final battle. When the two encounter one another and start fighting, Inaho asks Slaine to surrender, knowing full well that he wouldn't even though he has another objective. At the end during the last confrontation, Slaine remarking that he has always hated the color orange collides with Inaho. As the two gradually start to enter the atmosphere, Inaho uses his Sleipnir to act a a drogue shoot to help the Tharsis. Slaine saying that its not possible for them to survive, the two crash in the sea next to a beach. Slaine making it to shore, met Inaho with a gun aimed at him. Slaine smirks while tapping his forehead, signifying to Inaho to shoot him in the head. Slaine was stated to have died and was held responsible for the assassination plot for trying to kill Empress Asseylum, which is what started the Second Earth-Mars War. This is however not true. After the events of his capture, he ends up being held in an undisclosed prison. (AZ2: "Inherit the Stars")
He holds a deep admiration for Princess Asseylum, and he is also grateful to her for saving his and his father's lives. Slaine taught Her Highness what he knew of Earth; the sky, sea and the creatures that live there, because of this, the Princess develops a deep admiration for the planet. (AZ: "Princess of VERS", "Then and Now") . Slaine also seems to harbour romantic feelings for the Princess.
Like Asseylum, Slaine seemed to have taught Her Highness to a certain extent of what he knew about Earth. Lemrina has admiration for Slaine as he has gained real power in Vers despite being Terran born, and she finds great satisfaction in this fact as she herself was neglected by her family for being an illegitimate. Lemrina also seems to harbour unrequited romantic feelings for Slaine and marries him so Slaine can ascend to a Vers prince and consolidate his power.
Cruhteo held much contempt for Slaine for being Terran born, despite his attempts at helping Princess Asseylum and trying to convince her not to go to Earth. Later on, he believed Slaine was a Terran spy and tortured him for information. Cruhteo eventually understood what Slaine had been trying to do and apologized to him (while the latter was unconscious); however, the two never had a chance to reconcile as Saazbaum interrupted and killed Cruhteo to save Slaine (or so they both think).
Unlike many Martians, Saazbaum treated Slaine with respect despite the latter being a Terran, as he was the son of the man Saazbaum owed his life to. He saved Slaine from Count Cruhteo (at least he intended to do so) and revealed to him that he is the instigator in the assassination plot on Princess Asseylum's life. After telling him his motivations for starting the war, he let Slaine make his own choice on which side he wanted to take. After the time-skip, Saazbaum seemed to have become closer to Slaine, treating him like his own son as well as naming him his son and heir. Saazbaum was even impressed when Slaine decided to betray him in the end, dying with a proud smile when Slaine called him "father" for the first and last time. Slaine seemed to look up to Saazbaum as he inherited and valued many of the latter's own ideals and teachings. However, Slaine never forgave Saazbaum for putting Asseylum in a coma and eventually betrayed him, although he was visibly upset and acknowledged Saazbaum as his father in the end. While Slaine originally had intentions of stopping the Second Earth-Mars War, knowing that Asseylum had wanted peace, Slaine came to understand it would make no difference as someone else would do the same in starting another war like Saazbaum; thus, Slaine came to decide in taking over his step-father's footsteps and resume the war with Earth.
Slaine sets out to find Inaho because he is the pilot of the orange Kataphrakt that managed to defeat two Orbital Knights and that he saw that the Princess was alive with him. He intervenes with the UES Wadatsumi's battle with the Hellas and assists Inaho. But after the Hellas is defeated, Slaine aims at Inaho worried that United Earth was exploiting the Princess but Inaho shoots down Slaine's Sky Carrier down first due to distrust and as far as he knew, the only Martians who knew Asseylum was still alive were assassins. Later, Slaine stops Inaho from approaching Princess Asseylum's body, shooting him without hesitation when Inaho draws a gun on Slaine. (AZ: "The Boys of Earth", "Childhood's End")
Harklight is Slaine's subordinate. He treats Slaine with the utmost respect despite Slaine being younger and a Terran, because Harklight comes from a lower class family, and looks up to Slaine as an example of someone who has climbed the ranks of nobility in the Vers Empire, the land of no opportunity. Harklight's admiration and loyalty to his master had continued to grow over time, especially as Slaine had given him the Herschel. His devotion had gone to the point where, knowing that his master wishes to kill himself with the war coming to an end as an act of redemption for everything he has done, Harklight and a handful of soldiers chose to show a last stand of loyalty to Slaine. While all of them were aware that they would fruitlessly fight a losing battle, Harklight and his allies preferred to go down with Slaine's cause, knowing that all of the young lord's intentions were noble, as they went to engage the last battle of their lives with the intention of dying proudly while being steadfast to their beliefs; exceptionally moved, as the loyalists began to display their last moments of valor, Count Barouhcruz chose to join in to show his own last moments of admiration towards Slaine. (AZ2: "Toll for the Brave", "Inherit the Stars")
Initially, Eddelrittuo thought lowly of Slaine since he was born on Earth. After returning to the Vers Empire, she began to warm up to Slaine and she spent much time learning about the Earth from Slaine in Asseylum's medical chamber.
- Kensho also voiced Todoroki Raichi in Diamond no Ace alongside, Natsuki Hanae, who voiced Haruichi Kominato.
- Slaine while smirking taps his head with a finger signify to Inaho to shoot him in the head after the two crash land on the Earth. Count Saazbaum did the same thing with Slaine during the end of events on his Landing Castle.