Requirements

Ok there's two methods of doing this.

1. You can dump and load textures on dolphin emulator which tricks it to loading the skin on said costume.

2. You can add additional skins and add your custom textures to vanilla soul calibur 2 or replace one in plus can be use on dolphin, modded Nintendo GameCube console and modded wii.

Dump/Load Texture Method:

1. Go to a character Select screen and find the skin you want to edit.
2. When you've found it, go to your graphics settings in Dolphin and click Advanced. Select Dump Textures and return to the game.
3. In order to only dump the ones, you want, quickly press the "Y" button (whatever your change costume button is set to) and only go back around to the costume you originally wanted. You should see the model reload. Go back to the Graphics settings/Advanced and disable Dump Textures. Your textures will be ready in your \Documents\Dolphin Emulator\Dump\Textures\GRSEAF folder. or PLUSC2 if using plus not vanilla.
4. Edit them how you would like in photoshop or gimp. Save them as a PNG with the same file name they started with and copy them to \Documents\Dolphin Emulator\Load\Textures\GRSEAF where they'll be available in-game. or PLUSC2 if using plus not vanilla. NOTE: You can resize the textures to be HD, but keep in mind the layout of the texture before hand.
5. You can test your textures on the fly if they're saved in the Load directory by going to your Graphics Settings, Advanced, and selecting Load Custom Textures. You can click it to display them in-game and deselect them to show the default skin. I'd also recommend selecting "Prefetch Custom Textures" so when you load up the game the textures are loaded into RAM. Video guide here by Jin: https://www.youtube.com/watch?v=cFEYTmVsSCU

Adding Skins Method:

1. You're going to need. soulcalibur 2 vanillia or plus, gamecube rebuilder, olkviewer, and sc2css
2. Open GameCube Rebuilder (https://gamebanana.com/tools/6410) click on image and select your sc2 iso. then right click the root.olk disc and extract to desktop.
3. open up olkviewer, then click file open. go to your root folder then find root.olk. Open it and then extract file 5.olk then open that up in olkviewer.
4. File 5.olk are costumes and weapon slots. Find your character costume https://github.com/dcoopers120/Soul-Calibur-2-Plus/blob/main/sc2_everyone_character_slot_for_olk_and_greed.txt
5. The top part are jpn files and bottom are English files.
6. So for example if u want to give someone a fourth costume. extract one of their pkgs files if u replace one of them click on the pkg and hit replace.
7. Click the example slot below third costume then hit replace. olk going to refresh with new costume slot added.
8. Now click the plus icon next to pkg. then click file 1.vmg this character model for all the characters. and on the right, you'll see cmpr files those are the textures. to see them right click and extract. there are .dds files
9. once you extract your texture open it up in a photo editor program make your changes. then save it as .dds
10. Now find those save .dds and import them into olkviewer.
11. now once you done. click file then find file 5.olk and replace it. then open root.olk and click on file 5.olk below file 4.olk and hit replace that with file 5.ok
12. Now open up sc2css https://github.com/dcoopers120/Soul-Calibur-2-Plus/blob/main/sc2css_v0.4.1.zip
13. Click File then open. Select Main.dol for Gcn. main.dol file is inside the root folder under syscctem data. but it's call start.dol
14. Now you see all the characters. click on the character you did and increase costume count and copy the costume icon and background slots into the 4th slot.
15. Click Edit. Character Info. then scroll down to your character and increase costume count. then hit file save.
16. Re open gcn rebuilder. click on root. then select your root folder then click root again hit save. save new iso as whatever name. then hit root again and click rebuild.
17. now you have your new skin and iso. here a video guide to help. https://www.youtube.com/watch?v=D62Z-81BPOc