Question about pronoun usage
 

Link is a YouTube clip, which contains spoilers from the finale of the Super S arc in Sailor Moon.

At the 4:49 mark in [SPOILER]this video[END OF SPOILER], while Helios is talking with Endymion, he abruptly changes his choice of pronoun from "boku" to "watashi." Why is this? I'm aware, for example, why a person would discern between "ore" and "boku/watashi," but I wasn't aware there was any kind of honorific discrepancy between "boku" and "watashi." Isn't the difference only a matter of either masculinity or gender neutrality?

"Watashi" is a gender neutral and polite pronoun. "Boku" is used by young men and boys and is informal. I think the change in pronoun from "boku" to "watashi" in the video clip could be that he wants to show respect to the person with whom he is talking.