Martellus Lucullus
Martellus Lucullus is the Captain of the Cobalt Scions Third Company. Known as an articulate proponent of the patient rationality of his original chapter, some regard Lucullus as a paragon of traditional virtues. Others, though, say that the one-time Ultramarine is a man who will always do the right thing, so long as the right thing helps cement his place in the history books - including his offer to cross the Rubicon Primaris and help found the Cobalt Scions.
History
Martellus was born to the wealthy Luculli family of Nova Thulium in the Macragge system. While his elder siblings could look forward to inheriting various farming estates, assuming they demonstrated the aptitude for it, young Martellus was always getting into fights, and tarnishing his family's name with unruly behaviour. Eventually his parents suggested that if violence was all he wanted, he could perhaps join the Ultramarines and repair the damage he'd done to the family's reputation.
Martellus could tell his parents didn't want him to go, they just wanted him to start behaving himself, so he called their bluff. The very next day, he added his name to the aspirant slate in his scholam. His parents, who had never shown any interest in military affairs, were horrified. In Martellus' young mind this seemed like a victory.
Whilst Martellus would never regret what he became, and took great pride in making it through selection, he did regret the hurt it caused his family. At the same time, it frustrated him that other families in Ultramar boasted for generations if one of their relatives had been accepted into the Adeptus Astartes.
Over the coming decades, Martellus Lucullus would gain (and lose) a great many brothers. He marveled that he should happen to be alive when the primarch was returned to them, and horrified by the damage visited upon Ultramar by the Plague Wars of Mortarion. He moved through the ranks, eventually joining the veterans of Captain Agemman's First Company.
Few ever survive long enough to wear terminator plate, but even that wasn't enough to satisfy Lucullus. In his desire to become a legend of the chapter - something hard to do in a room full of legends - he had dedicated himself to mastering every weapon in the Ultramarines' arsenal. This flexibility and devotion was one of the things that had earned him his place in the First, but eventually he accepted that to be a true legend, being a warrior was not enough. He needed to become an officer. It was Lucullus, therefore, who suggested to his Sergeant, Justarian, that the squad should volunteer to help found the Cobalt Scions. It was, after all, a cunning way of jumping himself ahead of the competition to become a captain, even if that meant swallowing the bitter pill of leaving his Ultramarines livery behind.
Of course when Justarian and the others died, Lucullus' grief was heavily coloured by guilt. But for his ambition, they might have lived on. No matter how much he knew they had accepted the risks, he swore he would never again allow his own ambition to lead others into danger.
After a century of leading marines in battle, Lucullus' demeanour is almost entirely alien to the boy he once was. The mistakes of the past have made him cautious, slow to anger, and patient. In conversation he will always seek to learn everyone else's opinion before revealing his own. He earns the loyalty of his brothers by valuing their counsel. On the rare occasions he has attended the senate, he speaks pragmatically and with no obvious bias, infuriating senators with his intractability. He is known for having a strict moral code and arguing against any wayward behaviour, whilst self-deprecatingly acknowledging that he says this from the position of one whose mistakes have cost him.
His inflexibility lands him in trouble on occasion, as does his lack of initiative. By default he prefers to adopt a defensive strategy then counterattacking as soon as he sees a weakness in the enemy's assault. This is an approach he takes both militarily and socially, and does so with such regularity that he is considered predictable by those who know him.
For all his talk of service and virtue, Lucullus remains obsessed with his legacy and how he will be remembered. This leads some to see him as vain, a perception not helped by his willingness to be sculpted, painted, interviewed, profiled, or written about. It is hoped, therefore, that he will not be tempted to abuse his power as Consul to annex Imperial worlds for the glory of his chapter. His admirers deny this possibility, pointing to his strict moral code, but his detractors observe that with limited room for promotion in a chapter, he would gain plenty of reputation if he were to pay unwelcome homage to the Five Hundred Worlds.
Given how recently the Cobalt Scions entered the Eridani Sector, it is as yet too early to tell whether Lucullus will cleave to either of those extremes.