When Zidane equips a thief sword, Add Status does nothing and can be unequipped to free up Magic Stones.
Soul Blade does not work with daggers equipped (whose status is applied via Add Status instead).
Soul Blade is nigh guaranteed to inflict the targeted enemy with the ailment from Zidane's currently equipped thief sword (viewed with while in the menu), unless they are outright immune.
Final Fantasy 7 Remake Intergrade Intermission Review - Half-Measure
