By the time of Mobile Suit Crossbone Gundam: Ghost Tobia, now going by Curtis Rothko, is more laid back and very friendly even to strangers. Though he tends to apologize a lot much to the confusion of Font Baud. He has taken up a code name and keeps his true relationship with Belle a secret though it isn't long before it's revealed at he's in fact her father. However, when it comes to battle he's still as determined as ever and years of experience has made him into a skilled veteran who takes all battles very seriously.
Another thing to note is that though he's blind he doesn't talk about it all that much nor does he treat it as an impairment. This is demonstrated when he still chooses to pilot and even when against the EMS-TC04 Desphys he asks for help instead of blaming his blindness for hampering his abilities.
Curtis Rothko has also gained an overprotective side towards his daughter Belle. Such as when he warns Font that had he made a pass on Belle on Jupiter he would be executed. Though Curtis Rothko says that he's kidding he whispers into Font's ear that he better cease with the passes anyway for his own good. When Font later elopes with Belle, Curtis is seen torn between executing Font or marrying his daugther to him.
Ten years have past since the armed resistance of the aristocratic fraction, the Crossbone Vanguard, was subdued. Tobia Arronax is a young boy originally from Earth. An exchange student on board the spaceship Smashion to Jupiter from Earth, he becomes wrapped up in the Jupiter War during a surprise attack by a group of space pirates who call themselves the Crossbone Vanguard, causing him to hijack a Bataras mobile suit before encountering Kincade Nau in the Crossbone X-1. After then finding poison gas containers on board the ship, he discovers that there were actually hidden agendas among those in the Smashion and in Jupiter itself. He is attacked by Prof. Karas, an agent of the Jupiter Empire who had originally posed as a teacher for Tobia, only to be saved by Kincade.
After being saved by Kincade, he was taken aboard the pirate ship, the Mother Vanguard and was convinced by its captain, Berah Ronah, to join them. The pirate group's true identity was revealed to be a guerrilla group resisting the secret faction within Jupiter, the Jupiter Empire, which intends to conquer Earth. Determined to help bring an end to the war, while Kincade continues to support as a mentor, Tobia becomes a better pilot despite being often short tempered, letting his emotions get the best of him in battle.
The first mobile suit designated as his own is a captured EMS-10 Pez Batara that had been repainted with an eye to identify it as a member of the Crossbone Vanguard. With his awakening Newtype abilities Tobia used the Pez Batara to destroy an EMA-04 Elefante on the moon Io that threatened to destroy the Crossbone Vanguard's fighting force. Tobia and the Pez Batara were later captured while en route to Earth. After participating in a gladiator style battle against the XM-X2 Crossbone Gundam X-2, while armed with only a pistol, Tobia managed to escape the Jupitris 9 with Bernadette Briett in the Gundam's core fighter.
He then becomes the pilot of the new XM-X3 Crossbone Gundam X-3 to help the new Crossbone Vanguard in their quest to oppose the Jupiter Empire's plans. With the Crossbone Gundam X-3 Tobia would defeat an EMA-06 Elegolea, the Death Gale Squadron, and Crux Dogatie's EMA-10 Divinidad. The final battle against Crux Dogatie left the X-3 damaged beyond repair.
With Crux Dogatie defeated, Berah Ronah and Kincade Nau retired from active fighting, entrusting leadership of the Crossbone Vanguard and the pilot designation of the XM-X1 Crossbone Gundam X-1 Kai to Tobia, where he later upgraded it into the XM-X1 Crossbone Gundam X-1 Kai Kai "Skull Heart" which bared a similar motif to that of Tobia's destroyed XM-X3 Crossbone Gundam X-3.
Three years after the war against Jupiter, Tobia and the Crossbone Vanguard once again cross swords with the Jovians. He rescued Europa Dogatie from Jupiter Empire Mobile Suits that were pursuing her. He was initially met with hostility by the Jovian until she relented after seeing Bernadette Briett alive. It is mentioned that he closely resembles a Jupiter Empire soldier named Curtis, Europa's true love who was killed in a skirmish against pirates.
Europa explained that the Jupiter Empire, this time under Callisto's Light and Callisto's Shadow is once again planning to attack Earth. This time, there were plotting to destroy the Earth Federation's capital and other important cities with a Colony Laser (Divine Punishment) from Jupiter. When she informed Tobia that they only have two weeks until the laser is fired, he had to act fast. Minovsky Drive originally used by the Mother Vanguard would be the only way to get to Jupiter on time to stop the attack but the Mother Vanguard was destroyed.
Tobia remembered a project taken by SNRI that experimented with miniaturizing the Minovsky Drive. Being the only hope, the Crossbone Vanguard quickly moved to the SNRI facility on the moon that housed the experiment: the F99 Record Breaker.
The officials of SNRI were initially hesitant on lending the Record Breakers but agreed. Suddenly, Jovian forces led by Callisto's Shadow started attacking the facility. The attack destroyed the Record Breakers, their data and spare parts, making it now impossible to use. Tobia attempted to fight Callisto's Shadow but he was nearly killed by the mysterious pilot with the Skullheart badly damaged as a result.
With the Record Breakers unusable, the Crossbone Vanguard was in a huge dilemma on how to reach Jupiter in time. However, SNRI presented them a footage of an Anaheim Electronics experiment that also experimented with the Minovsky Drive, codenamed "Project Icarus". The footage saw the project entering the atmosphere and was thought to have perished. However, Tobia saw that it survived instead, using the "Wings of Light" the drive creates to protect it. Minoru Suzuki warned that the mission to Jupiter will be suicidal so a team of skilled pilots will have to be assembled. Seeing the "Project Icarus" as the only remaining option, Tobia took Europa, Minoru and Mitchell Derek Nar with him to Earth in order to search for the whereabouts of the experiment and recruit skilled pilots that can help fight the Jovians.
After arriving on Earth, Tobia first started his mission by attempting to recruit his former mentor, Kincade Nau to join the suicide mission. However, after hearing that the former pirate is expecting a second child, he chose not to recruit him due to the slim chance of survival. He then went to recruit Burns Gernsback, one of his former adversaries. He agreed and advised reuniting the Death Gales squadron.
Burns took Tobia, Suzuki, and Europa (who was currently in disguise) to a restaurant. Tobia met Giri Gadeucca Aspis. One of the members of the Death Gale Team. He was now working as the cook of the restaurant and grew much taller than Tobia over the years. Tobia explained the Crossbone Vanguard's position and the Zeus's Thunder project to Giri. Tobia tries to get Giri to help the Crossbone Vanguard's mission, but Giri refused. Telling them that he is a chef now and he will not get involved with the pirates. He also told them that he is still loyal to Jupiter Empire. Europa revealed her identity to Giri and told him that her brother Calisto was now the president of the Jupiter Empire. The information on Calisto being the new president greatly angered Giri. Her appearance with the Crossbone Vanguard shoked and angered him. Questioning Tobia why is she here with the Vanguard, but was interrupted when Calisto and his forces attacked the area. Everybody went outside and met Calisto without his mobile suit, with his mobile suit forces.
Tobia was instantly knocked down and pinned by Giri. Telling Tobia that he is still a soldier of the Jupiter Empire and is loyal to Calisto. Calisto revealed that he was able to find out their location because of Europa, insinuating that she is a spy. Europa denied it, but Tobia tells her that he still trusts her and believes her too. Calisto laughed at Tobia and Europa. Revealing to them that she is a spy because he can read her thoughts, even from a long distance. Calisto then ordered his forces to kill the Crossbone Vanguard as he ordered Europa to get on the Elcopty. Calisto walked to Giri and wanted him to swear his loyalty. Giri spat on Calisto and attacked him. Telling him that he is still a soldier of the Jupiter Empire, but will not serve under Calisto. Burns and Suzuki saw the opportunity and attacked the soldiers who were holding them up. Bernadette piloted the Crossbone Gundam to fire at the enemy mobile suits. Tobia got up and took cover from the fire fight. Calisto ran away to the Elcopty, but Europa picked up a gun from a fallen soldier and chased after Calisto with Tobia running after her.
It has been 17 years since Steel 7 and the blind Tobia Arronax now goes by the name Curtis Rothko. At one point he has a daughter, Belle, with Tetenith Dogatie though their relationship is kept a secret for unknown reasons. Strangely enough while Curtis Rothko has clearly aged Tetenith Dogatie looks nearly exactly the same, only a bit taller, as her younger self from 17 years ago. The reason for this is never explained. It is also revealed that prior to the start of Mobile Suit Crossbone Gundam: Ghost Curtis Rothko would discover the X-0 Crossbone Gundam Ghost and an alien life-form living on a meteorite that would be named Angel's Call though it would later be stolen by Erin Schneider, a Jupiter empire loyalist who saw through Curtis's true identity as Tobia. Erin intends to trade Angel's Call with the Zanscare Empire, which is constructing the Angel Halo aimed to paralyze the Earth.
Eventually, Curtis Rothko, along with Belle who insisted on coming, would locate Font Baud after he accidentally stumbled upon information regarding the Angel Halo that was on the net. Curtis Rothko reveals that he doesn't want to get Font Baud involved, however, due to his discovery and the opening of the file containing information on Angel Halo it means that the Zanscare Empire will stop at nothing to kill him. Thus Curtis Rothko offers Font Baud to come with them or die here. At this point, the Zanscare Empire attacks in MW544B Sandhoges and Curtis Rothko reveals the X-0 Crossbone Gundam Ghost after it brings down a fog over the battlefield.
In no time Curtis Rothko makes short work of the MW544B Sandhoges, with Belle commenting in front of Font Baud that Curtis Rothko is her father, and retreats into the Mobile Suit Museum. Here he takes a breather and while Belle searches for a usable mobile suit for Font Baud and her to escape, Curtis Rothko allows Font Baud to ask him any question he wants. Much to his surprise Font Baud just wants to know about the X-0 Crossbone Gundam Ghost. Since he promised to answer his questions Curtis Rothko reveals that the X-0 Crossbone Gundam Ghost was supposed to arrive at the Crossbone Vanguard 20 years ago but due to an accident the transport ship was destroyed. Thus the X-0 Crossbone Gundam Ghost remained dormant for 20 years until Curtis Rothko found it.
With that out of the way, Belle finds a working MS-06 Zaku II though it's only there for events and has no real weaponry which isn't much of an issue since Curtis Rothko is sure he can handle all the fighting. At this point, the Zanscare Empire attacks again and Curtis Rothko meets them in the X-0 Crossbone Gundam Ghost. Just as he has achieved victory an unknown mobile suit appears and attacks.
Curtis Rothko is at a disadvantage and asks Font Baud to explain what the mobile suit looks like since he can't rely on what he knows to determine how to fight it. With some pressing Curtis Rothko reveals that he fights through sound and his knowledge of enemy mobile weapons. However, since this one is unknown he's literally fighting blind against it. After some fighting Font Baud describes the mobile suit to him and Curtis Rothko realizes it's the melee specialized EMS-TC04 Desphys belonging to Thoucus (short for Thousand Custom), a group of renegade-turned-mercenaries from Jupiter. With this knowledge, thanks to Font Baud, he's able to avoid defeat and eventually kicks a building on top of the EMS-TC04 Desphys so that they may escape before the situation grows worse.
When the EMS-TC04 Desphys breaks free and gives chase Curtis Rothko forces the colony to open its exit under threat of being fired upon. With that out of the way, they escape to the Manzana Flor. Once they have escaped Font Baud is examined by the crew and the very next day Curtis Rothko meets Font Baud and warns him to stop making passes with Belle for his own good. At this point, they receive an announcement from Tetenith Dogatie and during this time Belle reveals in front of Font Baud that the woman in the projected image before them is her mother.
After the speech ends and the Crossbone Vanguard is revived Curtis Rothko is taken by surprise that all the responsibility has been passed on to him. However, he resigns himself to this and mutters about politicians, outside forces, and how peace is drifting further away. Curtis Rothko than brings Font Baud to another room and reveals what Angel's Call really is and how devastating it would be if it was used now of all times since it has no counter. Thus he employs Font Baud as a hacker and goes on to explain in great detail on past and current events.
Curtis gets wind of Thoucus contacting the Zanscare Empire, and decides to ambush the Zanscare mothership to extract intel about the whereabouts of Angel's Call with Font's hacking skills. It turns out that Thoucus is making a rendervous with the Golden Egg squad commanded by Kizo, and the latter purposely leaks this information to Serpiente Tacon so as to lure them in to fight with Thoucus in order to test latter's strength. While Curtis and the Serpiente Tacon successfully disable the Zanscare mothership to extract intel, they are ambushed by a League Militaire squad led by three black Victory Gundam. The battle is further thrown into disarray when Thoucus emerges to engage both Serpiente Tacon and League Militaire, and eventually outmatching both. With the help of Font, Curtis singlehandedly defeats the three black Victory Gundams, but is overpowered by Thoucus. He is able to retreat with Font's improvised diversion, bringing along the pilots of the three black Victory Gundams.
- In SD G Generation DS, Tobia can be obtainable early in the game rather than in the Encore Session if the game is played on Special Mode in either UC or AU routes.