In order to best understand Ketriporis’ situation, it’s time to give a brief overview of Thracian family history.
Originally, Thrace was under the leadership of one guy – Kotys I. Since Kotys had three sons, he decided to divide his kingdom into thirds instead of letting them fight it out. Of course, this only delayed the squabbling.
His three sons were Berisades, Amatokos II, and Kersebleptes. Berisades sucked because as far as we know he didn’t mint any coins. Either for that reason or for another, he died. His son was Ketriporis.
Ketriporis’ main problem was that his uncles wanted his territory. Kersebleptes, in fact, had a plan. He schemed with Athens to take Ketriporis’ territory for himself. It was then that the young Ketriporis did something particularly foolish that did them all in.
Ketriporis joined an alliance with Paeonia and Illyria against Philip II. This royally (he he) pissed him off, and he invaded Ketriporis’ kingdom and made him a vassal. This messed up Kersebleptes‘ plan, since it was one thing to take territory from the immature Ketriporis, but it was a completely different matter taking it from the far more powerful Philip II.
Eventually, Philip did take over all of Thrace, including the kingdoms of Amatokos II and Kersebleptes. As for Ketriporis, we assume he remained a vassal of Philip, but there’s no more information about him.