Immortal world houses all of the anthro characters even though they can still die there but most of them can be brought back to life. Mortal world is where the humans, elves, etc etc live.

Humans are the weakest, heavily rely on materials and not able to cast spell without specialised training and blessing. However, they are the most adaptable. Jidari has been guiding and providing them with materials for hundreds of years in order for them to survive the hostile environment that they are in with the cost of them worshipping him as a god. He only does business with them in the Between worlds Realm where 2 worlds collided. He cannot directly descend to the mortal world and help them without alerting other "gods".

Vin is pretty new to this stuff but he knows a bit about non-arcane technology...