Defeat Darkrane Kynari BestSoldiers, Darkrane Kynari Protectors, and Darkrane Kynari Snipers in Anantor. Then, talk to Thumbs at the Salia Pond. Use your quest tracker to see your progress.
Thumbs: I'm Thumbs! I'm Hakks's younger brother! I'm Thumbs: Isaiah's second son! HiiragiKagami: Oh! You're Sir Hakks's brother. Nice to meet you. Thumbs: I heard a human and a Pran are giving my brother Thumbs: help. I want to thank you for that! NakanoAzusa: Oh, well - thank you, Thumbs. How old are you? Thumbs: Thumbs isn't young! HiiragiKagami: You look young! Thumbs: No, I'm not young! My brother wouldn't have sent Thumbs: me here to attack Anantor if I were young and Thumbs: unreliable! I'm here to take my father's revenge! NakanoAzusa: It's a little dangerous. Thumbs: No! Do you want to see? HiiragiKagami: See what? Thumbs: I'll go kill those traitors right now! Right now! I'm on Thumbs: my way! HiiragiKagami: Whoa, stop that little kid!