Question: are theoden and aragorn related?
Answer: Yes, Theoden, Eomer and Eowyn, knew that Aragorn was the heir to the throne of Elendil. Aragorn was no longer hiding his identity, he was stepping up to the plate and was ready to take up his crown. Bearing Narsil/Anduriel, the ancient sword reforged, wearing the gem, flying the standard Arwen made for him.