If you want the primary locations, just look at the Ancient Teleportation spells.
Anywhere a teleport goes, probably had a Teleport Obelisk.
Guess could think of it as a precursor to the Lodestone network, just for Zarosians.
I'm not sure they'd have been used for normal commercial transport.
Something like this, especially back in the 2nd Age, was probably just reserved for senior Zarosian officials.
Even then, given that these things take a long time to power up, they may have been even slower "back in the day". Maybe even a full day cool down time, unless you were a Mahjarrat or powerful mage, at which point you could just charge it up some yourself to transport your party.
Next, I'd guess these were only in play
late
in the empire. Probably constructed (or fully constructed) about the time Zammy took down Zaros.
With the empire suddenly in decline and invaded on all fronts, using the network was potentially more dangerous than anything else.
Another wacky theory: when the power of the Stone was used to wipe out Forinthy, the obelisks got a super charge, but also got randomized.
The destruction of Forinthy was a massive release of energy. Who's to say the Obelisks didn't absorb some of it?
This would allow the Obelisks to teleport more frequently.
Flipside is that where as before, you could do "something" to direct it to your intended destination. But that ability got destroyed somehow. (A focus may have existed at one point. Or perhaps just an innate nature of the obelisks.)
It wasn't until someone came out with the Wilderness Sword, that a method for directing it came about.
28-Jun-2018 00:11:28