Summary...
Teleportation Circle
- Ritual site, platform and arcane circle in the subterranean level is a powerful teleportation circle; in theory it would allow safe and accurate teleportation of groups of people over vast distances.
- Elven crystals used in combination act as a simplified way of setting "coordinates" rather than having to reinscribe part of the ritual circle any time a user wishes to change the destination. This is not without flaws as the crystals erode through time and use but the premise is intriguing and could be adapted.
- Damage to the circle is mostly superficial and could be repaired and modified to allow more traditional methods of setting coordinates (unless a method of rapidly growing Elven crystals can be determined); this would require funding for appropriate material components.
- Practical value of the teleportation circle still to be determined, rough calculations indicate that waste energy released at the destination would potentially be devastating and grows exponentially with both distance and volume.
- Suitable sites ("convergence points") could reduce the waste energy; prepared ritual circles at a destination could further reduce the waste energy.
- Based on the nature of the damage, one possible theory that the damage to this location was caused by magical waste energy from a teleportation. Given that this is a convergence point and a prepared ritual circle the distance and/or number of people involved would need to be significant.
Illusion
- Technically this is a fairly normal illusion spell (more accurately many different interwoven illusion spells to work from different angles). However, the nature of illusion magic is that it creates images, it does not hide existing things; using illusion to screen a real world scene as a form of camouflage is unusual and the complexity to have the illusion work so well from different angles is impressive.
Preservation
- The preservation magic over the tower is nothing revolutionary, functionally similar magic is used by by the university to help preserve and maintain some of the oldest scrolls and tomes. It is unusual only in the scale, given that the tower itself is stone it seems inefficient to maintain the spellcraft over the entire location - it would make more sense to specifically target bookshelves, foodstuffs, etc.
Mana Crystal
- The arcane circle on the roof is interesting, it draws in ambient magic from the surroundings to provide a "trickle charge" to a properly prepared mana crystal; it is just enough to maintain the illusion and preservation spells woven through the tower as well as a few other minor enchantments.
- Outside of a convergence point the ambient magic drawn in would be negligible, even at this location the amount of magic drawn in can be highly variable (with the crystal acting as a buffer to prevent rituals cutting out).
- Damage to the mana crystal caused by prior researchers on site means that it is now leaking magic faster than it is charging. The magic in the area is highly variable but rough calculations indicate that the current rituals on the tower will last for 3 to 6 months.