I wonder if it's alright to say "I'm glad"
You didn't kill the enemy that you chased for years (or you killed the enemy you have been chasing for years,didn't you)
You don't look too happy. You didn't want him to die?
What does そのことですか here mean? Some そのことですかわからない maybe?
I also took as 討ったじゃない as "You didn't kill" but could it be "You felled him, didn't you"? I guess the confusing is because he didn't kill him himself but he still died.