Because he himself had a Mage Tower, one far more magical and powerful than the Dark Tower—Mesnoel's Tower of Dominion.
Like the Insight Gemstone, the Obsidian Crystal Ball is its ruling key, except that the shape and name are different.
With a single thought, Gaven and Philancy simultaneously appeared within the Dark Tower.
There is also a main control room here, located at the very top of the Dark Tower, where only being present could give you full control over all aspects of the Dark Tower.
Instinctively, Gaven compared it to the Tower of Dominion.
Unlike the Tower of Dominion, the Mage Tower named Dark Tower did not possess such complex abilities; it specialized only in guiding and balancing the negative energy of Mosantiel City.
In terms of overall performance, Mesnoel's Tower of Dominion was something the Dark Tower could only dream of achieving.
