I'd like to rip sprites from Romancing SaGa: Re;universe, but need help

[Falconpunch]

As you guys might know, SquareEnix released a gacha game based off the SaGa series, title Romancing SaGa: Re;universe, and I'm interested in helping ripping some sprites from it.

However, when I got access to the apk files, I didn't find any sprites or artwork images in it. Did I do something wrong? Is there a way I can get them?