Flameburst Rod

All three versions come from the Tavernkeep in trade for Defender Medals. Progression gates the upper two: the Flameburst Cane appears in his stock once any mechanical boss is dead, the Flameburst Staff once Golem is. There is a second gate that catches new players out. Until you have finished an Old One's Army run, these summon nothing in the open world. That first clear is recorded against the world and against the character who did it, so afterward any character visiting that world can use sentries there, and the one who cleared it keeps the ability in every other world too.

It lobs fireballs that burst on impact and set what they touch alight, upgrading to a harsher burn at the higher tiers. The burst covers a small square around the point of contact, which is enough for two or three enemies and no more, so it will never mulch a wave the way the other towers can. The limitation to build around is the firing arc: it cannot angle shots steeply upward and simply ignores anything hovering above it. Stand the towers on a raised platform rather than the floor and Etherian Wyverns and Kobold Gliders drop into its line.

The Apprentice and Dark Artist set bonuses add no damage at all, which surprises people who equip them expecting a boost. What they add is reach. Sight range, targeting cone and projectile speed all climb steeply, and the Dark Artist version widens the explosion into something that genuinely catches a group. The reach is what matters tactically: you can plant the towers safely in the middle of the arena and still have them covering every lane.

This is the weakest of the Tavernkeep's sentries on raw output, and its consolation is discipline. It keeps hammering whatever is at the front of the push instead of wandering onto a target behind it. The pairing worth building is with Explosive Trap sentries under Huntress or Red Riding gear, since those coat enemies in Oiled and burning an oiled target goes much faster. Fabled is the modifier to hunt for, though a heavily stacked summon build tips the top tier over to Ruthless. If you decide you want a different tower entirely, shimmering one of these converts it into the Ballista of the same tier.