Most towers and baileys are defensive, protecting defenders from attackers. This keep tower and bailey is used to protect everyone else from what is within.
Some time magic users are less magical than one expects.
The district gets its name by the good sized walls that are painted a bright blue that mark the magic district. That wall is watched by the Witchhunter guard.
Helioglyph (his magical name) is a Talismonger, a maker of charms, talismans, holy items, and so on. This is the place where those seeking fine craftsmanship and good symbolism come. If you are looking for enchanted items, go elsewhere.
No one is allowed to do harm to those of Highest/ Imperial rank, those of the Imperial household or those related within two steps of blood. The second tradition is an executioner must be of a higher rank than those he executes. This leads to "issues" when someone tries to harm a member of the Imperial clan or when these members are subversive. Such people are often killed by the being chained under a giant bell. They die within a day or so from the vibration, but they die untouched by Human hands.