There a quite a few quests, each one involving legendary pokemon as your main target
The Living VolcanoeEdit
The Living Volcanoe is one of the many quests that you can partake in. This quest follows the giant dragon pokemon Groudon who the local townspeople call the Red Dragon. You can find Groudon hiding inside of Mount Kelabara a large Volcanoe found deep within the Seminile Mountain Range. Upon your journey to find Groudon (Who can be found anywhere in the volcanoe, even sleeping in the lava) you will encounter many different mountain dwelling/fire type pokemon some of which are Skarmory, Heatmore, Onix, Steelix, Aggron, etc.
The Terror of the SeasEdit
The Terror of the Seas is a boating quest that takes place in the middle of the Atomic Ocean. In this quest the local townspeople are scared of the great "Terror of the Seas" a large whale looking pokemon that dwells at the bottom of a large trench called the Earth's Scar. The pokemon if you have'nt already guessed is of course Kyogre. You will be located onto a small fishing boat with a fishing rod. You have a small chance of catching him on your first time you'll most likely engage another water type pokemon like Tentacruel, Lumineon, Seaking, Hauntail, or even Basculin. Once you catch Kyogre you're suppose to spear him with a(n) harpoon and rell him in. However his shear power is enough to drag you, your crew, and the entire fishing boat underwater. There you engage in combat armed with weak scuba armor a harpoon, and your patner pokemon. May the Odds be with you.