Shadowfang Keep is the second dungeon that has undergone changes after the Shattering. The normal hums and voidwalkers have been removed in favor of more Undead and Worgen type enemies. Just as with Deadmines, Shadowfang Keep has new quests for both sides of the conflict.
While previous bosses were mostly Worgens, the new bosses are all Forsaken or Ghosts. The first boss is Baron Ashbury, who tends to use damage over time and healing to himself and his helpers. It's best to damage him after his DoTs have worn and some time has passed to heal up. The second boss, is a return to Silverlaine. Most of his attacks aren't very powerful, but he can summon extra Worgen helpers as his hit points fall. The third boss is once again Springvale, none using a mix of Death Knight skills. It's important to deal with any adds that may still support him and only really hammer this boss once the other foes are dealt with.
The fourth boss of Shadowfang Keep is Lord Walden, an Undead mage who also sports some deadly damage over time and instant damage attacks. He doesn't have any real support so there is no need to worry about any adds. The fifth and final boss is Lord Godfrey, a deadly hunter. He summons a number of ghouls quite often, but these adds aren't very threatening and have low health. Godfrey can do some serious damage with his pistol barrage, but this move can be dodged with some good timing. Otherwise, most of this boss' abilities are pretty straight forward tanking.