One of the elements we loved most about the original Ultima Underworld was how the world felt like a real place that existed without you.

Our forum-goer Setho10 put it well: “I think maybe the best way to sum it all up though would be to say that the world reacted as you would expect. AI reacted in a far more realistic way than in any game I had played before. I specifically recall wounded enemies fleeing from battle. It was the first time in a real time game I can think of where enemies did more than follow one simple basic pattern. These AI had different states and that was impressive and immersive in a way that is just indescribable. […] It felt like this was a real living world not a set of levels created by a designer, and more than anything that is what makes Underworld so impressive to this day.”

We knew that Underworld Ascendant needed to be designed as an interactive world, but also one that lived and breathed when the player wasn’t around. Everything from the lighting to the creatures’ animations are all being considered as integral to Ascendant’s world-building.

One element where this immersive ecology has been coming online is mana, which our lead designer Tim Stellmach describes as, “Not only is it the resource used to cast spells, it is actually concentrated in packets in the material world. Characters recover mana by touching and consuming these invisible free-floating bits of mana in the air.”

How does that affect the world? The entire in-game ecology is based around it. Wisps – benign, ethereal creatures who float throughout The Stygian Abyss – feeding on mana in the environment and excrete “sunlight” (infrared, ultraviolet, and visible light).

They fill the role of “the sun” for the flora and fauna in The Stygian Abyss, they are an essential part of the underground ecosystem.

Meanwhile, undead creatures, rather than being seen as capital “E” evil, have a parasitic relationship with mana, devouring it to ambulate in a sad parody of life and giving nothing in return.

Another recent aspect of this in-game? This “sunlight” leads to flora, which is eaten by various fauna, like our “ambient” creatures, who generally mind their own business in the world, but have interesting behaviors that the player can exploit to their advantage.

Our current favorite ambient creature is the Deep Slug, who can be baited with certain types of food and leaves useful effects in its wake, like a flammable slime trail. Toss its favorite food into the patrol path of a few enemies or by a wooden support of an archer tower, add fire, and enjoy. (Feed it something else interesting? And discover the results…)

We recently peppered The Umbral Mire area of the Underswamp with Deep Slugs, loaded the level up, and soon came across a scene where we witnessed a few careening by in distress, pursued by angry skeletons. We’ll have more visuals to share on the Deep Slugs soon!

We’ll definitely need to tune interactions between different creatures, but it’s nice to see the ecology starting to take hold.
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