Sets a game variable. Variables can be character or party specific. Most variables take a single byte, but some take two or four. Note the chart below. The variable is applied to the currently selected character or to all if selected character is 0 or 8.
For those arguments that take 2 or 4 values, watch the endianess. ie, 0x10 0xA0 0x86 0x01 = 0x0186A0 Experience = 100'000 Experience.
Also, the set_nothings can probably be expanded and implemented in future games, if needed.