User blog comment:Kogath/Monster Hunter 4 Ultimate for the Nintendo 3DS/@comment-28303251-20151014210824/@comment-26421638-20151015130830

You should do this Quests to get Dense Marcoal and to Use the Demolisher...

http://monsterhunter.wikia.com/wiki/MH4U:_Gathering_Hall_Quests#Advanced:_Escaped_Convicts

http://monsterhunter.wikia.com/wiki/MH4U:_Gathering_Hall_Quests#Advanced:_Lab_Partners

And after this you have to do a Village Request wich Requires 3 Azure Rathalos Shards and 1 Purecrystal...

And... Remember that In The Battlequarters you cannot use the Demolisher at the Beginning... You must to wait 15 (or 20?) minutes to use the Demolisher...