(I should mention that some people want to call Edo/Ryo something else now because "proshipping" has kind of taken on a different meaning to English speakers). For newer shows and media, i think shippers (supporters of a ship) just combine the characters' names.

I think it's because they can both see spirits! A lot of slightly older English speaking fandoms from the 2000's or so assign relationships (shortened to "ship") they like a random word and then stick -ship to it. Like Judai x Manjome is "rivalshipping," or Edo x Ryo is sometimes "proshipping"

It's a whole genre it's beautiful

a side note, but: 'no talent likenesses' will be used. So, Chris Pratt and whoever else are protected (for the moment). But the animators and designers who made these characters you are now willingly feeding into the slop machine designed to replace them...they're not considered talent.