I'm looking for a manga that had something to do with these details: 1. MC's sister is the hero/companion of hero's party, and maybe uses swords 2. the MC either drowns or is throw into a lake/river by another member of the hero's party because of jealousy over his sister 3. the MC is not part of the hero's party (I think) 4. the MC makes a deal with some dragon right after he is thrown into the lake/river and gets special powers If anybody can help me with this that would be great.