FAIRY TAIL Vol 34

From the Kodansha edition

Outraged by the way Yukino has been treated, Natsu goes on the warpath and challenges the master of Saber Tooth to a fight! Back at the tournament, the wizards prepare to face Pandemonium, a castle built out of magic containing one-hundred terrible monsters, the most powerful of which are easily capable of taking down a Wizard Saint. But when Erza, desperate to reclaim Fairy Tail's honor, wins the right to go first, she declares that she'll take on all one-hundred at once!

Source: Anime News Network Encyclopedia