In a very neat easter egg (not to mention a nod to a certain segment of Gladiolus’ fanbase) you can get Gladiolus to play shirtless through all of Episode Gladiolus‘s story, and have his strength boosted by 200 points as you do so. It’s a fun unlock, although it does require you to play through the DLC multiple times.
But hey, you get to look at Gladiolus playing shirtless, which, if that does something for you, is worth it, right? So you probably want to look into unlocking this ability for yourself. If so, then follow the instructions below.
To do this, you need to:
Beat Episode Gladiolus. This unlocks Attack Mode
In Attack Mode, get a score of 500,000. This unlocks Rugged Attire
Rugged Attire is is Gladiolus playing shirtless- you can now select it in the main story mode
The video below has some tips and tricks for scoring 500,000 in the Attack Mode.