The Caedaren homeland had been lost a scant while earlier, and the majority of the Moon Guard - comprised earlier of Hearts - had been destroyed. There was a need for the pair of the Sun Guard. The reasons were traditional and ritualistic (one might say, superstitious). It had to be built from somewhere. Clearly, from the remnants of the Sun Guard, but that was hardly enough...
A number of prominent figures from among the Eyes and Hearts emerged, a few of them the remnants of the Sayluna clan. One of the surviving Saylunas was a prodigal son who had run off in search of better booze and to avoid getting drafted into the Hearts. Ironically, his drinking binge ended up with him joining the Eyes, who even then prided with their toughness.
Varus Sayluna, the prodigal in question and the current Carenda of the Bleeders, has said that he personally saw the reformation of the Moon Guard as an opportunity to get rid of a number of problems at the same time. One, the lack of the Moon Guard. Two, the fact that his family rarely spoke to him. Three, the threat of Sheadaren scouts. Four, finding the colonies that had left in search of a warmer climate. He was all for it, especially if it meant him getting to order people around instead of the opposite. (In the end he did get that post, but he had a predecessor.)
He has also noted that it wasn't hard for him to find others that agreed there was a threat and a debt to pay to the Sheadaren, and he willingly joined them, lobbing the then legendary lieutenant of the previous commander of the Moon Guard with the rest of them. Most of 'them' were his own family, who were startled to realise the tattooed, gigantic man in his prime had once been a savant and casanova that enjoyed basking in the sun. The others were Hearts, Sun Guard or Moon Guard, that felt guilty over being too weak to fulfill their duties, and Eyes that desired vengeance while knowing that a single Caedaren was hardly a match for a legion of Sheadaren.
To this date, this is what the Senet are - the basis of the Bleeders. They are the vengeful, the bitter, the sneaky and the deadly. In the future the ratio of former Eyes in the Senet decreased, as the Mivet and Vovet were created. The Senet co-operate with the Eyes very gladly, as the two are strikingly similar and complement each other well. But, then again, everyone gets along with the Eyes.