@Kenju:
2 possible explanations:
A) The inhabitants of the game world are still "only" NPCs and as such no living beings in regards to the real world's laws.
==> So the agreements from the Geneva Convention do not apply to them.
B) The inhabitants of the game world are so sentient that they are considered "living beings".
--> Then however their nations and governments must be recognized as autonomous, too.
That means their countries and governments have the right to decide their actions, agreements, rules and laws themselves .
Hence they must be informed about international rules and laws that you want them to sign and then they have the choice to adopt or refuse those rules and laws.
Before or without their agreement no law or rule from our world can be applied to their world.
The agreements from the Geneva Convention were not signed by the dragons or anyone else in the fantasy world.
==> So the agreements from the Geneva Convention do not apply to them.
Conclusion:
No matter how you look at it none of our international laws and rules apply to the fantasy world.