In the extended edition of the movie, Thrain is held captive at Dol Guldur, but in the book he is believed to have died long before the dwarves and Bilbo set off for Erebor.

电影的加长版里，瑟莱因成为了多尔哥多的俘虏，但是在书里，他在矮人和比尔博出发前往孤山之前就死了很久了。

youdao

In the film, Radagast discovers the Necromancer of Mirkwood (in the tower of Dol Guldur in Mirkwood) and then hastens to warn Gandalf and the rest of the company.

FORBES: Review: The Hobbit: An Unexpected Journey and The Mooreeffoc Effect

For example, the delightful Sylvester McCoy plays nature-caring wizard Radagast the Brown, who tracks down the source of mysterious illness amongst the fauna of Mirkwood to the supposedly abandoned keep of Dol Guldur.

FORBES: Review: The Hobbit: An Unexpected, But Very Welcome, Journey