Follow up: I’ve heard he died in battle with the Scythians, is this true?

He certainly died in battle with the Scythians, but there is question over wether it was the Massagetae or the Derbices, because the historians Ctesias and Herodotus give two different stories. Generally though, Persians, after a military education from age 5 to 25, would fight un battles up until they were 50. Cyrus however, perhaps for morale, joined in battles personally.