Despite the current races having a common ancestor they are still seperate species and cannot produce offspring.
The gods can be split into primary and secondary gods. Primary gods originate from magical energy as described earlier, there are currently 9 of them. Secondary gods however are mortal lifeforms which have managed to gain enough magical power to attract more power and make their own plane of existance, there are currently 5 of them.
Inside a gods plane of existance the laws of physics can be quite different from the ones we know. Gods are unbeatable on their home turf there they have power that is beyond challenge. However they are considerably less powerful when visiting other gods. No mortal creature can actually create a portal capable of moving a God to the material plane.
Mortal creatures with magical power may pull on energy from the Gods, this is considerably easier than pulling on energy from the universe itself. Unfortunately The gods can withold power from people that don't behave the way they want. Additionally when pulling on power from a God it is aspected after the God, magic pulled from the gods has a mental and physical aspect. The Mental aspect allows magic that fits tightly with the Gods personality while the Physical aspect links into what the God routinely shapes in its home Plane.