A leshy (Polish: Leszy, in English sometimes spelled Leshii or Leszi), also known as leshen or spriggan in The Witcher game series, is a forest monster that is described as something that "lives only to kill". When they kill something or someone, they do not leave much for any carrion eaters.
In the Wiedźmin: Gra Wyobraźni PnP RPG, leshy is described as a forest-dwelling, iron-resistant, highly intelligent monster. For unknown reasons, many peasants consider him to be a spirit that protects the forest. In reality, it is a very dangerous creature that hunts woodland creatures and lone wanderers. It has the ability to polymorph.
In its natural form, it is a wildcat-sized creature that looks like a cross between a wildcat and a bear, with mighty fangs and sharp claws. It mostly lurks among the tree branches, from which it quickly jumps on its victims. It usually devours the whole prey. Its mightiest weapon is the ability to shift shape. It can morph into a humanoid being that looks like a harmless, old man or into a tree branch that is practically identical to real ones.
In this graphic novel for The Witcher 2: Assassins of Kings, our hero, Geralt of Rivia starts his adventure by getting contract on ancient leshy from castellan Lazare, but monster later turns out to be something else.
Leshens in The Witcher 3: Wild Hunt are ancient and powerful forest spirits. Possessing a deer skull as a head and tree-like limbs, a leshen can call for aid from crows or a pack of wolves.  Furthermore, in some circumstances, a leshen can only be "permanently" defeated if the person it chooses as its "link", or familiar, is banished or killed as well. Geralt may also have to destroy a leshen's warding totems to rid a forest of its presence. 
Information from the official the Witcher 3 site Edit
Humans have long been fascinated by the wild wood — living in its vicinity was the source of tales about creatures ferocious and benign, friendly and hostile. As they started to settle deeper and deeper into the forests, respect for the unknown diminished. Lumber was gathered, stone abodes were built. As the pestilence that was humanity grew bigger, so did the forest's and its inhabitants' wrath.
At the heart of the forest lies a secret. In a place born of darkness and primeval nature, resides a mighty and terrifying guardian. Immune to human steel, it is believed the leshen is nature's way of protecting the forest and the animals that live within it from the threat humans started to pose upon their ravaging expansion deeper into the lands.
Along with the animals it commands, the leshen became a force to be reckoned with. Sometimes worshipped, this creature can heal other woodland animals and summon nekkers or crows to protect the forest. Its attacks are slow, but deadly — be cautious not to get shackled by its underground roots.
Bestiary entry Edit
- We never hunt in these woods. Never. Even if it means the whole village starves.
- — Mulliver, ealdorman of Hoshberg in lower Aedirn
- Leshens dwell in dense, primeval woods. Fiercely territorial creatures, they hunt with stealth and cunning as their only companions. They use their inborn magic to control the plants and animals within their territory — and so, when stalking them, half the battle is merely getting near enough to strike. Leshens old enough to earn the appellation "ancient" wield advanced skills and tactics that make them particularly dangerous.
Combat tactics Edit
Leshens do not fight alone. They can summon swarms of crows to distract and harass their enemies, and even call upon wolves to fight with them. They seem to prefer nighttime and darker underground areas.
When facing a leshen, watch for them to dig their rootlike arms into the ground. This is a sign that they are commanding the roots to strike. This attack has surprising range, does heavy damage, hits a reasonably sized area and can only be foiled by rolling away from it. Leshens are slow but powerful melee fighters, and can cause serious injury if allowed. Dodge or roll away from the swipes of their claws.
They also have the ability to turn into a "smoke form"; they will raise both arms above their head and with a swirl of dark smoke, disappear. Note while doing this any attacks on them will be at least partially reflected, and will break Quen.
They have been seen to be very, very vulnerable to a series of Fast Attacks and will, without fail, go into Smoke form after taking 4 or 5 hits. This will also teleport them to a random location but they will stay in smoke form which is openly visible as a small moving cloud of swirling smoke, and attacking it does no damage until they appear. They won't attack while in smoke form, but if you're right next to them when they reappear they come out swinging.
Igni, and any bombs that can potentially cause fire damage, such as Dragon's Dream, are useful against leshens. While a leshen burns, it will be unable to defend itself.
Leshen can cross your path in The Witcher: Adventure Game. This creature is very hard to defeat, level Gold.
To defeat them you need:
Successful Sword: Receive 2 VP.
Failed Sword: Suffer 1 Death for each Sword you are short.
Behind the scenes Edit
The term "leshy" comes from the Slavic term for "forest" ("las"). All Slavs had great respect for forests, mountains and water. A leshy was something like the master of the forest. It was everywhere in the forest and did not like when someone entered into its dominion, but it never left the forest.
If a human spied a leshy in the forest, it was most likely that he had lost his way. Folk tales told that to find his path again, he had to turn all his clothing inside-out.
- ↑ 1.0 1.1 Source: The Witcher 3: Wild Hunt Displays a Reactive Open World with Organic Combat, last visited 2013-06-21