Keth as he should be called casually in his people's grammar, is one of the Anchai'rae, a race from the Agris cluster. Ordinarily, Keth would have a Pair name along with his Self name of Keth, but that title was stripped from him when his brother died.
As his title demands, Tae'keth is stoic, and incredibly formal, except in battle. Having spent a full century, like many Anchai, dedicated mostly to mastering the intricacies of Anchai speech, Tae'ekth's speech almost never dips below the level of the most formal and refined events in human society. But beneath his bulletproof skin (which all Anchai possess), Tae'keth is a tormented individual. His past is ripe with tragedies centuries past, and his future seems equally bleak. As one of the Order of the Elder Flight, Tae'keth is excepted to put the needs of the Anchai'rae before his own needs, his society's wants before his wants, and to obey without question his few superiors, even if he is ordered to his death. There is also the issue that he has no mate and no sibling. Nearly all Anchai'rae are born with a twin, most fraternal, some identical, but only a few Anchai are born without a twin. These Anchai are shunned from general society, forced into menial positions at the bottom of society, and treated as less than possessions. Tae'keth was not one of those unfortunate few at birth, he had a brother Atha'Koros, to accompany him throughout life when he was still known as Atha'Keth. But his brother is now dead, which would have, had the Primarchs, the pair of Anchai who rule over their entire society, intervened, left him honorless and destitute. For excellent leadership in a battle long past, Atha'Keth was given the title of Elder (oddly enough at 300 years old in a society where 800 years is the average lifespan, and a small percentage of the population is essentially immortal), saving him from a fate worse than death in Anchai society.