Hmm nice to see that someone is picking up a Digimon Game,
it doesn't happen often
Thought I was the only one haha.
But it would be nice if you could name which one it is as we have two in the database.
Anyways the problem you are encountering here is classic.
Obviously Katakanas use all the same width size.
While the ABC is not. Ultimately this will lead to more letters doing this.
Now since we are dealing with the Naming Entry Screen you could check out the width of the Katakana
an example approach would be to check for the letters in a tile viewer (Tile Molester is powerful if you know how to use it.xD)
, figure out the width and then,
set a break or if I'm not mistaken a hook point in a Debugger like http://www.romhacking.net/utilities/338/
This would lead sooner or later to figuring out the tile size. Now if for every letter the tile size is defined singularly, tedious as it might be you could
do a workaround and define for every letter a custom tile size.
If there is one tile size for every letter (which I think is likely) you could try to half it and see if that would work.
If not, I guess this is where ASM would come in as you would have to write a Vfw unless the hacker who abandoned the project has taken care of it.
I haven't seen the game nor do I know which one you are referring to so this is just some very general advice which most likely won't be applicable to the game unless you tell which one it is,
then I might be able to help better.