If you mean the final boss, the "grand master of all things bad", i recommend you to pack many reviver seeds, about 4~6, and also a few sleep and x-eye seeds.
Firstly, you should try to get wigglytuff out of the picture temporarily by throwing the x-eye or sleep seeds at him, then take your time to focus on the other "minions". Wigglytuff will be out of action for awhile, so you're pretty much safe from him.
If you have a Pokemon that knows a room-hit move, such as earthquake, discharge or vacuum cut, all the better, you'll be able to take out the minions in about 2~3 turns. For me i had a lv45 riolu and a lv45 pikachu, but i heard that 40 is a safe level to be. My pikachu had discharge, so it was no problem getting rid of the rest of the guild easily.
For wigglytuff, try to hit him with your strongest moves, throwing the x-eye and sleep seeds if you need to, he will go down fast to your combined efforts. Make sure you only take him on after you have taken down all the other guild members!
Have fun! Hope I helped.
defeat dialga and defeat wigglytuff and go to luminus springs
Defeat the guild in mystifying forest i(t was pretty difficult).The most hardest to knock out is wigglytuff (The Grandmaster of all things bad).
You first see them in Wigglytuff's guild and then they help you defeat regigigas.
Very carefully .-_-. Seriously, if you cant beat the Wigglytuff guild then you're just sad. Wigglytuff will cheer you up.
After you defeat Dialga, you'll be required to beat Wigglytuff and all of the members of the guild. Once you beat them, a spring will be unlocked for you to visit. You can evolve Pokemon here.
Its the same as Time/Sky! Someone who doesn't know! Oh my god! To unlock Wigglytuff, go to the Wigglytuff Guild. 1st, defeat your enemies. Last, your there! At the Wigglytuff Guild!
Even though I haven't played sky, I would imagine you graduate from the guild and get10,000P WOOT!
you dont have to defeat arceus. his only mention is as a statue.
Nobody, all you do now is do missions and get new friends
your two Pokemon have to be level 99 and then talk to diglett bring him to his dad. team raider will sees you then you have to defeat them Wigglytuff appears and says:"WOW!!!That was amazing!" "I am promoting you to the MYSTERY RANK!" you get to do a lot of new missions in that rank
defeat him 2
Once you graduate from wigglytuff's guild you will live in the hollow chamber in shapedo cliff