Shamans are cowardly creatures. They try to run from the aisling who has its attention and cast spells from range. When they reach the edge of spell range, they will come back just close enough to cast spells at you.
A Shaman tries to stay two (2) or three (3) paces from its target. If it is further away than two (2) paces, it will move toward the target. While moving toward the target, a Shaman behaves exactly as a Common Beast. When it is closer than three (3) paces from the target, it will retreat to stay out of melee range.
A retreating beast moves the opposite of the Common Beast. When a Common Beast would move north, a Retreating beast would move south. When a Common Beast would move east, a Retreating beast would move west. If the target pursues a retreating beast, it will stay in retreat until it gets to what it considers a safe distance, three (3) paces for a shaman.
Sometimes a shaman will seem to freeze in its tracks and do nothing. A shaman that isn't moving is casting a spell. After the spell is finished, it will resume moving as normal.
Melee fighters can become very frustrated with Shamans. As soon as a fighter closes with the prey, it runs away.
The best way to fight a shaman up close is to corner it. Surround the Shaman on all sides with aislings or blocks and it will be unable to run.
A solo fighter will have troubles cornering a shaman. Another alternative is to back a Shaman against a wall ((three or more blocks in a row, or the edge of the map)). The Shaman will walk back and forth between the space in front of you and one pace to the side. This tactic will take time, since you are only able to hit the Shaman half the time, but it is far better than chasing the wandering beast all over Astrid.
Spellcasters find Shamans ideal. The Shaman is very helpful in fact. It will stay within range at all times and never close to do melee.
Trapping Shamans can be a little more difficult than trapping a Common Beast. A good rogue can always guide the Shaman where she wants it to go, but its close/retreat nature makes it slightly harder to control.
The simplest way to take advantage of a shaman is to hide and set a line of traps. Then get behind the Shaman and attack it. The Shaman will move directly away from the rogue and the rogue may chase it, keeping it in retreat and attacking all the while.
Another way that is slightly more dangerous does not require hide. The rogue gains the attention of the shaman by taunting or attacking it, then sets a trap. The rogue then moves away from the shaman and sets another trap. Repeat as necessary. As the rogue gets further from the shaman, it will be lured over the traps. A rogue using this tactic should be more wary of spells.