Since the Gem is a character, I would like to vote rather she may be added to the characters category, especially since she's in the character navbox. It doesn't matter if she's controlling a location. She's in the Gem category, and Gems are characters. As long as she's one with the clock tower, they are one and the same. Plus we consider Gems of similar caliber characters, you know the ones. The Clock Tower is in the Gems category and the Corrupted Gems category. She can't be in those categories without being in the characters category.
I vote for Support, to add to the character category.
Oppose I don't think the Clock Tower is a character.
To Mizukage's now-deleted response: Yes, however this is an article about the location and the physical place, not the gem that it contained. Since we haven't seen the physical form of the gem, there should not be an article for it, and the Clock Tower page should not have the character category.