Feral spirits are beastmasters trained to an unusual degree, even amongst other beastmasters, in fostering a bond between themselves and their animal companion that transcends normal communication. Such rangers know on an instinctive level the goals, desires, fears, and actions of their feral partner as intimately as the animal itself and the same is true in reverse. In the heat of the moment, feral spirits and the beasts with whom they travel are, for all practical purposes, one being.
Feral spirits gain this uncanny ability, which seems telepathic to the uninitiated, through a literal binding of spirits. How this is accomplished is not quite understood, though the primal power of the world is believed responsible for the unusually tight connection between ranger and beast, which allows the two to feel one another's emotions and thoughts as they come. The original inventors of the tradition of the feral spirit are also unknown, though many point towards the elves.
Although, like all rangers, feral spirits draw much of their power from physical training and technique, the hunters of the wild also carry with them an additional source of energy - their beast companion. Not only do feral spirits work their beastial allies as partners and friends, but they actually draw on one another's spirits to replenish their own, forming a spiritual link as a well as an emotional one. To the outside world this is made evident by the increased effectiveness both ranger and animal display when merely within sight of one another, as well as through the ranger's ability to recover from wounds and shattered spirits for seemingly no reason as their companion lends them some of their own strength.
A feral spirit's exploits also benefit from the shared connection, allowing ranger and animal to strike their foes simultaneously and with flawless coordination. Twin-soul strike, a highly advanced technique only used by experienced feral spirits, is one such technique, with both feral spirit and beast striking at once. Feral diversion, a less advanced and less showy technique, nonetheless relies on silent but flawless communication between ranger and beast.