Ok I looked at several games for the dakuten, and apprently while the majority of them use it above the text in the intra-lines, some games inline it as a " character, especially games with not too many text.
Namely, Rockman games, Kid Icarus, Castlevania II, Contra, and Battletoads inline the dakuten. I looked at Battletoads carefully because it's one of the rare NES games (if not the only one) that was developed in Europe and was later translated to japanese, which is interesting. It makes sense they didn't plan to have room for the dakuten in the original game, and had to deal with it when translating it.
In the case of my game it's weird, because in the weapon selection screen I'd have room for the dakuten between the lines, but when you equip the weapon, it's name is supposed to appear in the status bar, and here I will not have room for it because the line above is used for something else. Well so either I move the layout, either I inline the dakuten everywhere, or I do some code to inline it in the status bar, but place it in the interline on the menu screen.
And PLEASE someone translate this last sentence !!
DRAGON SWORD got its ancient power restored and became FIRE SWORD.
So I can get the total count of kana characters and begin my work.