No, he is not. He was the son of Aethra and king Aegeus.
Yes. a few are Theseus,Polyphemus(cyclops),Neleus,Orion,etc. Other than Polyphemus the rest of them are demigods. These are just a few of his childern, not all.
Poseidon had 56 children. The best known ones are Triton, Theseus, Orion, and Polyphemus. Polyphemus was a cyclops who lived on the island of Sicily, and he was blinded by Odysseus in "The Odyssey" by Homer.
Poseidon has many sons, but the most well known is Triton, herald of the sea. He is also one of Theseus' fathers, and also father to Polyphemus, the cyclops from the Odyssey.
Theseus was 18
Theseus' mother is Aethra.
Theseis is the story of Theseus
theseus wear a toga
Theseus killed the minotaur
Theseus got the sword from the rock that he pulled it from.From Ariadne
Theseus is Theseus in any language. Btw the language is Latin, not Roman.
Aethra, the mother of Theseus, mated with both Aegeus and Poseidon to produce Theseus.