User blog comment:Skeith9/Heroic Spirits Speculation/@comment-50.159.54.248-20140721200933/@comment-50.159.54.248-20140721205354

The Towe of Glass on the other hand is most likely how Merlin plans to equal or tilt the playing field to his advantage.

A Hyper-grade workshop/Alien realm type Noble Phantasm, that defends on the outside, while becoming a hell on Earth for those unwittingly entering the place.

An illusionary dimension that break the rule of "Reality must never must with Fantasy".

Weakness: High Prana up-keep.