Expert Collector of Blue Rockers Expert Collector > Page: 31 Acquiring Req.: Collect at least 50 Blue Rockers. Reward: When collecting Blue Rockers, the Collectable Item is doubled. Blue Knocker Lv 34 Blue Rocker's Natural Enemy Natural Enemy (31-40) > Page: 13 Acquiring Req.: Kill at least 90 Blue Rockers. Reward: Killing Blue Rockers grants you bonus XP. Blue Knocker Lv 34 Legendary Blue Rocker Hunter Natural Enemy (31-40) > Page: 13 Acquiring Req.: Kill at least 210 Blue Rockers. (Blue Rocker's Natural Enemy Title is required.) Reward: Killing Blue Rockers grants you bonus XP. Blue Knocker Lv 34