I'm not 100% sure if it's true or not, but apparently in the code of Guilty Gear Strive there's a model of Goku that bricks the game if he's deleted.
Absolutely true.
When they were building Dragonball FighterZ, they started by building out Goku with all the basic game mechanics. The code for mechanics like running, jumping or attacking is actually a part of Goku, and all other characters shortcut back to Goku for these things.
They built Guilty Gear Strive on the same engine, and to get a head start they just ported Goku into Strive and used the same shortcut trick. Every time a character does something, the code actually asks "How would Goku act in this situation?" and then modified that behavior for the character actually being played. If Goku cannot be found, the game crashes.
