Pokemon Brilliant Diamond & Shining Pearl: What Happens When You Find 40 Digletts in the Grand Underground?
Pokemon Brilliant Diamond & Shining Pearl don't do a great job explaining the mysterious meter in the Grand Underground area, so here's a brief guide.
Of all of the big changes found in Brilliant Diamond & Shining Pearl, those connected to the Underground are perhaps the most notable. Now called the Grand Underground, this sizeable subterranean area is home to a plethora of Pokemon, including many that can't be found anywhere else in the Sinnoh region. Though not quite as drastic a change, observant players may also have noticed a mysterious counter prominently placed beneath the player's mini-map.