The whole snake vs slug vs frog/toad ending totally reminded me of Jiraiya and Tsunade facing Orochimaru in early Naruto back in the day. Of course this would've come out roughly 15 years before that series even began, but still lol. According to the cultural notes at the end of the volume that's actually based on Chinese mythology which I may or may not have known at one point, can't remember. Tomorrow it'll be onto the first half of Omnibus 14!