Choose five permanents you control. For each of those permanents, you may search your library for a card with the same name as that permanent. Put those cards onto the battlefield tapped, then shuffle your library.
10/1/2008 This spell has no targets. You don’t choose five permanents you control until Clarion Ultimatum resolves. If you control fewer than five permanents at that time, choose each permanent you do control.
10/1/2008 The five permanents you choose must all be different. However, some of them may have the same name as one another. For example, you may choose two Empyrial Archangels and three Plains. If you do, you search your library for up to two more Empyrial Archangels and up to three more Plains and put them onto the battlefield tapped.
10/1/2008 If you choose a permanent whose name has been changed by an effect (for example, a Clone that’s copying another creature), you’ll search for a card with the new name, not one with the original name. Note that changing a land’s subtype doesn’t change its name.
10/1/2008 If you choose a permanent with no name, such as a face-down creature, no card in your library can be found with that name.
10/1/2008 You make just one search. (This could matter for cards like Aven Mindcensor, for example.)
10/1/2008 The cards all enter the battlefield at the same time. If one of the cards that’s entering the battlefield is an Aura, it must enter the battlefield attached to a permanent already on the battlefield. It can’t enter the battlefield attached to another permanent entering the battlefield via Clarion Ultimatum. If an Aura can’t enter the battlefield this way, it remains in your library.
10/1/2008 If you find a card that isn’t a permanent card while searching (for example, you chose an Illusion token and find the split card Illusion/Reality), that card remains in your library.