Apprentice's Hat

None of this is crafted. The Tavernkeep sells all three pieces for Defender Medals, and medals only come out of the Old One's Army, so the set is really paid for by running that event. His stock stays closed until a mechanical boss has gone down, which sets the order: kill one of the three, run the event at whatever tier you can survive, then come back and shop.

The magic bonuses are ordinary for this stage of the game. The reason to wear it is capacity: you hold two more sentries than a normal build, and the set pushes what they hit for on top of that. A mage in this armor fights alongside a small artillery battery instead of a single turret, and the turrets keep working while you are busy staying alive.

The Flameburst line gets specific help: much longer reach, faster shots, and a far wider arc of vision, so a tower planted at the edge of an arena actually covers the middle of it. Line three up before a mechanical boss or Golem and they contribute for the entire fight while you spend it dodging. Other staves benefit too, just differently. The Queen Spider Staff and Barnacle Staff get the slot count and the summon bonus without the targeting improvements, which is a fair trade when you want something that follows you around.

In a fight where you plant nothing, this is the weaker choice, because the other post-mechanical magic options carry either more defense or a stronger offensive effect and this one gives up both. Inside the Old One's Army the widened vision matters less as well, since those towers already shoot at whatever is closest along the lane, so swapping the hat for a Forbidden Mask and taking the summon damage instead is usually stronger. The Dark Artist set from the next event tier replaces this one outright.