User blog comment:Plexioth- xD/Monster Hunter 3 Ultimate/@comment-200.35.249.237-20130210193827/@comment-5946566-20130210205759

By the way, if you don't know it, the arena mode consist on quests on the Arena area where you fight one or multiple monsters with a choosen equipment they offer you. I say this because maybe you refer to a mode where you fight unlimited waves of monsters. This doesn't exist.

But it would be interesting...

By the way, yes, it includes new monsters and quests. I have seen quests consisting on  hunting a megaplesioth + miniplesioth. But I'm not sure if it wasn't an Arena quest or a normal quest...