Hobgoblins and Jogres were my worst ones. no idea how many I killed because I never kept track, but those were the two that I would repeatedly spend a couple days there then give up and come back later. Imps might also have been high because there was a long time that I'd kill any imp I saw, but eventually just spent a week by ardy monastery till I got the scroll. While I can understand the frustration, I still think that the game should have some rare and untradeable prestige drops, and champ scrolls fills that role well. Castle Wars I think is a lot worse a requirement than any of the champ scrolls. It takes longer than any of them does, and if your luck is terrible and you don't win a game then then its theoretically endless. It also encourages people to afk and not really play the game. I got imp randomly during a farm run :3