Their names, written backwards, as how Japanese was written in WW2. Ushio's seem to be a typo though.

Demundo said:

Their names, written backwards, as how Japanese was written in WW2. Ushio's seem to be a typo though.

I'm guessing it's how 潮 was read back then, as Ushiho is the reading on the japanese wikipedia for her.

CXu said:

I'm guessing it's how 潮 was read back then, as Ushiho is the reading on the japanese wikipedia for her.

Yeah, that's probably the pre-1946 reading, when kana spellings were weird old-fashioned.
Edit:
From Wikipedia: "The series of kana ha hi fu he ho are used to represent, in some words, the sounds wa, i, u, e, o, respectively."