A living soul! Well hello.Forester
Forester (Lesnik / Лесник) is a stalker who appears only in S.T.A.L.K.E.R: Clear Sky.
The Forester is an original resident of the Chernobyl area, who lived there long before the 1986 incident. He made a living as a park ranger in the Wormwood Forest (currently western Red Forest), alternating between tracking down poachers and guiding field trips. When the Chernobyl power plant exploded, he refused to be evacuated and stayed behind. 
He has a unique relationship with the Zone, as he seems to be able to always find his way through anomalies and can peacefully coexist with its creations. Furthermore, he has some knowledge of the more secret elements of the Zone, most notably Limansk and the Radiowave Institute.
If the Zone creatures are hostile to him, he is more than a match for them - he managed to kill a Bloodsucker with just a hunting rifle and hang its head on his wall as a trophy. He can also repair weapons and armor.
He resides in the tower of a shut down mine on the outskirts of the Red Forest. Forester is known throughout the zone by his ability to find a safe passage to sought reaches of the Zone. He tells tales of himself venturing into a Space Anomaly where he found himself trapped. He says the Zone itself granted him an artifact that allowed him to navigate out of the anomaly, in which he gave the artifact the name: "Compass."
Unfortunately, he was mugged by a group of Renegades, stealing his Compass. When Scar speaks with Forester during Scar's trek to find access to Limansk, Scar is asked to get his Compass artifact back from the Renegades in return for a safe route into Limansk. With the Compass returned, Forester helped guide a group of Mercenaries out of a Space Anomaly. Forester appears to be an accomplished hunter aswell.
His second one is to get his Compass artifact back from the Renegades in the old mine near his outpost.
When done he will reward Scar with an upgraded Vintar BC. This sniper rifle is upgraded to Tier 1 in accuracy, recoil and magazine size, but not the Tier 2 upgrades of reduced weight and increased flatness. Tier 2 upgrades cannot be installed. In fact, none of the upgrade options show up when offering the weapon to an engineer. However, the accuracy of Forester's Vintar BC is greater than that of a a tier 2 upgraded default Vintar BC, making it a superior choice for most stalkers.
- Forester is the only expert loner in the entire game.
- There is a glitch where the player can get as many upgraded Vintars BC as he wants - the player must pick the first one, close dialogue and again talk to Forester to repeat process.
- Originally, the Forester had a different appearance (wearing a toque with a blanket covering his knees) and he wasn't an expert in dealing with the Zone, that role was fulfilled by the Cartographer.