Wo used "Yo!". These hip new former abyssals and their crazy mannerisms!
That said, it makes sense as an entirely Japanese statement. "Yo", or rather, "よ" or in the Katakana-speaking abyssals' case, "ヨ" is often put at the end of sentences making declarative statements. It's one of a few statements that would oddly work the same way in either language, at least in some circumstances.
My niece acts just like that, especially with "Gwam". Always wants to stare at other people, and be in their business, but never wants to be directly seen so she hides if she thinks they might be looking.
Wo-class-san!Well, thank goodness!Is the ouchie on your head all better?Good for you!Why are you hiding...?Complete recovery, yo!Yes... thanks for asking.Is it already fine for you to be out on your own?