>>283252706
Cute. Anyway, the last line seems to be a bit mistranslated or maybe deliberately changed to keep people in suspense. The line was 相手は水の兄弟子 (Aite wa mizu no anideshi) or "The opponent is the senior apprentice of water". As you can see, the term 兄弟子 which everyone mentions is used here rather than a generic master.