Throne of Isengard is an incredibly powerful card, however there is a large risk when using it that it will serve as a double-edged sword, due to its passive strength and damage bonus to all Wizards. There are 6 Wizard cards in LOTR TCG: Gandalf, Radagast, Saruman, Pallando Deceived, Alatar Deceived and Radagast Deceived. 2 of these Wizards could potentially belong to your opponent, in which case ToI is actually helping them out rather than you. As such, it's inadvisable to use this card unless you have a dedicated Deceived Wizards deck, or your opponent has neither Gandalf nor Radagast. Bear in mind that, being an artifact, it's highly unlikely to be discarded; once you have played it, it will likely remain in play for the entire game.

The ToI's ability to make any minion fierce when Saruman is played is incredibly versatile, since it is not bound by any cultural restrictions. This means he can make almost any minion in the game fierce. He can also target himself, which is useful if you're using Fallen Istar's Stave over Saruman's Staff, as the only Saruman who is naturally fierce is Saruman, Of Many Colours.

• Archery and Wounding Fellowships, as Saruman has high vitality, and Deceived Wizards cannot take wounds.

• Artifact discard, such as Roll of Thunder or Something Draws Near
• Gandalf and Radagast
• Throne of the Golden Hall, since it prevents Saruman from fighting.

You may spot Saruman and make him fierce with this ability.

• http://lotrtcgwiki.com/forums/index.php/topic,1101.0.html