The Death and Taxes map was released in the recent 1.1.4 patch. The supporter requested a map that was reminiscent of a classic MMORPG raid fight, one that was built around the "Kite West" catchphrase of the Death and Taxes guild. He wanted the fight to be challenging and appropriately rewarding.
The supporter, Joel, Rhys and I discussed various concepts. These included a map where you could only walk to the west, a version where you dealt much more damage to monsters on your right, and a multitude of classic boss types. We eventually settled on a plan. Here is a diagram that was presented to the supporter. Joel later used this as a blueprint for the level design.
If you've played the map, you'll see that it has gone through some changes. We decided to have each form be reduced to 0 life before the transformation. This let us have the boss drop items and experience with every stage, rewarding players for bringing a full party through every stage.
We played with different room lengths - the map was originally twice the size of the current version, with thinner, longer passages. We widened the bridges to stop the boss getting out of sync, shortened the corridor lengths to speed up the initial walk through the zone, but slowed the boss to keep the fight length the same.
We experimented with the boss visuals. The boss forms started out as elemental themed skeletons, but we changed them to a cloaked figure with a scythe to better match the theme, and because the model looked better when scaled up to boss size.
The spawned minions began as summoned skeletons, but to prevent players being stuck while running away we changed them to a summoned version of Animated Weapons. This allowed the boss and players to pass through them, without the animated weapons being able to path through each other. To keep them with the "Death and Taxes" theme, they were renamed to "Collectors".
Here is is a screenshot taken during development of the map that was sent to the supporter. Almost everything visible here has changed with the released version.
To make the map appropriately rewarding, and to entice players into trying it out, the boss was given a 10000% increased experience reward. He also drops increased item quantity and has a huge boost to item rarity.
I hope you've enjoyed this history of the Death and Taxes map. If you're looking for a challenging boss encounter, give it a go!