Clay Road

I apologize if I wrote this badly.. Cause this is probably the hardest part to write during post game.. I mean how am I suppose to write boulder puzzle solving here, especially when I am already done with the game.. DX Frankly, I don't plan to write this but you might not know how to get to Regis without this..

There's 3 ways to go to Iccirus City.. One is from Mistralton City (6th gym)>Twist Mountain>Iccirus City.. Second one is simple, Lacunosa Town (7th gym)>Iccirus City.. The third one will be Driftveil City (5th gym)>Clay Road>Twist Mountain>Iccirus City.. And of course we are using the 3rd one.. You will notice that now there's no one blocking you enter the cave in Driftveil City.. This cave is none other than Clay Road..

For perfectionist: I suggest we go to Clay Road through another entrance cause it will looks more "complete" for your game.. You will need Strength, Surf and Flash here.. Get some Escape Rope too just in case.. Remember the place where you caught Cobalion in BW or the first time you met Cobalion in BW2? Go to Route 6 from Driftveil City.. You should know there's a Deerling Lab.. Behind the lab is a river.. Swim through the river (towards the right) and you will eventually see a cave..

The cave is dark here, you will have to use Flash.. The boulder puzzle is pretty simple.. Just walk one round counterclockwise around the cave and you can easily see how to solve it.. Here, you will be able to catch Anew as well.. After you are done, you should notice that on the south-east of the cave, you will see another entrance.. Enter this hole and you will now be at Clay Road..

For shortcut: You don't need Flash in Clay Road.. From here, just head upward all the way.. You will pass through two tunnels.. After the 2nd tunnel you will be at Twist Mountain's Icy Rock room.. There's 2 other entrances.. The top will lead you to Regigigigas' room.. You will need to solve boulder puzzle here.. You will need to capture all 3 Regis and bring them here in order to awaken it.. Now it's just frozen, you won't be able to catch it yet.. After you are satisfied starring at it, you can leave this room..

So now head for the 2nd entrance.. From here, get your way to Iccirus Town.. After you have healed your Pokes, you might want to go back Twist Mountain and head to Mistralton City from here.. If I remember correctly, trainers here like their Pokes to explode.. There will be a nurse somewhere in Twist Mountain, so have a safe journey.. :)

For Regis: IF you started from Driftveil City.. Just use the mining cart on the east.. On the way, "Strength" whichever bolder you see cause it will be your future shortcut.. Once you ride on the cart for 4~5 times, you will eventually reach an empty room with just a person standing there.. This will be the place where you can catch Regis.. After you have caught them.. Just get out from there, you will notice without the help of the worker,  you can't use cart.. So you have to choice but to push the boulder nearby.. Then head to the tunnel at the north.. Same like the above, you will reach Twist Mountain's Icy Rock room..