- Isis' and Osiris' plan for resurrecting the Earthlords seems excessively complicated. Rather than collecting Josh and Sophie from various points in spacetime, taking them to modern times, and raising them as their own, all while pretending to be Elders in turn pretending to be humans, in order to use their power to open a gate to the past... wouldn't it be easier to use the four swords of power? Cernunnos was able to use them, so their power seems to only repel Elders. John Dee used them to open a gate to the past in the fifth book, so why couldn't they?
- My guess is that only the Gold and Silver could use the swords to harness Abraham's pulse. If Iris and Osiris had tried to use the swords, they could have used them to enhance their powers and kill Elders, but they wouldn't have been able to harness the energies needed to create the gate they wanted.
- We haven't seen any indication that they work both ways. If they opened a portal to the past, it might be that Isis and Osiris can go to the past, but the Earthlords can't pass it to get to the future.
Headscratchers / The Secrets of the Immortal Nicholas Flamel