Is it correct to use the word "戦うて" instead of "戦って"?

Question

I'm watching a Japanese TV drama. It is the story of a student whose body sometimes is possessed by the spirit of a samurai. When the body of the student is owned by the spirit of the samurai, the student uses words that may belong to old periods. I want to know whether the use of the word "戦うて" instead of "戦って" by the student in the below conversation is because of aforesaid reason or not: "わしが その騎馬戦とやらで戦うてみせよう。"

By the way, please explain the function of "やらで" in the above sentence.

Answer 1

• Yes, 戦うて (pronounced タタコーテ) is an archaism for 戦って. It's an ウ音便 version of 戦いて (pronounced タタカイテ), which is an old form of 戦って (see this).
• Xとやら means "what you call X", "something/someone called X" or "so-called X". This is a quotative-と followed by this やら, but you can think of it as a fixed suffix-like expression. This usually has a nuance of being doubtful (i.e., "It's called X, but I'm not sure what X is or whether X is a correct name"). A samurai should be familiar with real cavalries, so he might have found it strange to call this game 騎馬戦.