First, you must have a circular area around the target. For example: Assume that the target is a Dumahim vampire (the most common in Nosgoth). Now, without using autoface, run a complete circle around the vampire until Raziel is followed by a trace of blue energy. This energy, once fully invoked, will "constrict" the vampire, causing it to be momentarily stunned -- and allowing ample time for you to finish the it off. The Constrict ability has odd effects on humans. They are as follows:
1. Certain humans, once you begin the Constrict ability, will act as though they plummeted into water. If you do not finish the ability, they will "drown".
2. The human will get stunned when Constrict is half finished, allowing you to stop and feed on their soul.
3. The most common and normal result is that the human will instantaneously die.
The Constrict ability is required to complete the puzzle in the Chrono-chamber. Also, make sure to return to areas of Nosgoth you have already visited prior to gaining that ability. You will find that Constrict can be used on many things, and may open up useful secrets (such as Eldritch artifacts, Glyphs, and life force pieces). Constrict does not work on Kain and will not work underwater.
