Just found what I wrote down way back when the episode aired.
GUYS Ocean was first mentioned in episode 3 so I think their appearance was long overdue. I was not disappointed. I love everything about this episode. Seawinger made an impressive debut, and I especially love Isana's character. Crew GUYS clumsily and valiantly trying to cover up when someone (Mirai) inadvertently giving away Mebius's identity was hilarious (although a bit over the top), and more so when it was revealed by the end of the episode that Isana already knew from the beginning.
Due to my inability to understand much Japanese, I don't know why Isana wanted to keep the fact that he was a captain a secret. However, the history he had with Araiso seems to be interesting.
Mebius's final cutting was so cool (poor Arigera), as well as the one he used to save Isana. Missed Mebius's transformation scene but since it's a stock footage anyway maybe I haven't missed much.
I never expected to even like Isana (portrayed by Kohei Murakami), considering that I totally disliked Masato Kusaka (Murakami's character in Kamen Rider 555), not to mention the preview made Isana looked somewhat like a bad guy. The fact that I totally love Isana says a lot about Murakami's acting ability. Isana is such a fun character to watch and I would really love for him to return in future episodes.
Crew GUYS Japan, you guys should be grateful that Isana is such a good guy; he even lied (I think) to his own follower to keep Mebius's secret.