Warriors of Ulric reads:

" Action: When a player declares a zone to attack, move this unit from its current zone to another of your zones "

May the controller of Warriors of Ulrich declare a zone to attack if there are no units in his battlefied in order to move Warriors of Ulrich to the Battlefield and attack alone?

Yes. Declaring the target of the attack and declaring attackers are separate steps. It is not a requirement for the declaration of an attack that you have units in your battlefield, or even any units in play at all.

In fact, you could declare a zone to attack, move the Warriors, and then not declare them or any other attackers, and skip the remainder of the battlefield phase.

Thank You! I appreciate the help.