Water

His eyes narrowed as he studied the damage that his attack had inflicted on the Abyssfeeder specimen that he had attacked. It wasn't that he hadn't done any damage at all to its second inspection, he just realized that it was harder to tell because its anatomy was so undefined and hard to gauge.

But it was clear that it was not entirely ineffective. And yet, he was a little wary of the fact that his strongest attack did not even hurt it all that much. One of the biggest points of concern was the fact that it didn't even need that much time to begin adapting to a certain offensive.

('It's adaptation timeframe is absurdly little.') Rui tutted.

When he compared it to his adaptation, at least, the adaptation speed of the Abyssfeeder species was much higher.

Of course, Rui adapted to opponents as a whole, not to a single attack. Their adaptation also worked on fundamentally different principles.