"Sudden use of first names...!!" Riku and Ryuu's "natural appearance" shown on TV conveyed that they are important to each other, and it seems like this is how they usually are.

Select a sentence or use the bottom play control. The current sentence is highlighted during playback, and you can move backward, forward, or seek to repeat it.

Turn translations or readings on in learning settings, and select unfamiliar words to view their meanings. Try understanding first, then reveal only the help you need.

Start with the displayed difficulty, then listen to or read a short section. If you understand the main idea with only a few lookups per sentence, it is usually suitable.