You can enter the 8 Digit card code to unlock the card at the Rent Counter and you can add it to your deck. Speedrun.com
If you don’t want to use hex codes but still want shortcuts, here are the fastest legit methods to unlock the toughest characters: yu gi oh gx tag force 2 cheats
But Syrus was already reaching for the lab top. “Just one peek. For science.” You can enter the 8 Digit card code