Like I said, You need to edit these files
\data\sprite\ÀÌÆÑÆ®\¼ýÀÚ.act
\data\sprite\ÀÌÆÑÆ®\¼ýÀÚ.spr
But don't ask me how, it's not my specialty.
Btw, I got these one from japan blog, which is scaled down from original size
ÀÌÆÑÆ®.zip
*Just check it yourself, I won't give any ss spoiler