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.