Seti II was the son of Mery-n-Ptah and Isis-nefert and the 6th farao of the 19th dynasty. Although being the hereditary prince to the thrown, he didn’t ascended the thrown immediately after the death of his father. It was Amenmesse who ascended the thrown and reigned for 4 years, where he came from and why isn’t clear.
Probably he was a son of Takhet, daughter of Ramses II, and Mery-n-Ptah.
He seems to be exiled to the Sinai and died there. Nevertheless his mummy was never found nor identified. The two women found in KV10, one of them would be Takhet.
Seti II usurped the thrown, maybe by force, exiled Amenmesse, and reigned for another 6 years.
He started building a tomb known as KV15.