What makes me so strong?

Question

I am strong. I am a

Quick whirlpool engulfing, radially third. You'll use it on puzzle
as sought dead French guy.

But not yet. Wait until you are told to. The puzzle comes here.

Pnwbra xpogpe

I'll even tell you what to do with it.

The first things go first. Go right where you ought
To get mentals collecting toll on road.
Then use my name as it is said above,
try not get engulfed in my vicious love.
This gets you from dark places underground
to shiniest parts of the Moon to be found.

The single "r" is present but in vain,
two first, two second and two first again.
The last thing you have to append here rests.
This is what you have a dozen times first.
There is something strange. Why "a"? Any clue?
This should be one letter that stands for you.

If you followed my directions, you should already know what makes me so strong.

What makes me so strong?

A little hint:

Most of the time you should work on some english word(s), so if you end up with complete gibberish, something went wrong.

Note that the answer to the classic "What am I?" question is essential to proceed, but it is not the final answer to the puzzle.

Progress (according to answers)

1. The first line of puzzle text and first hint refer to a keyboard layout: QWERTY with ASDFG below. (Xenocacia)

2. Using a QWERTY keyboard (As found by @Xenocacia), And shifting the the cipher text by one letter to the right and converting "P" to "A", the
   "Pnwbra xpogpe" decodes to "Aments caphar". (Sid)

3. "This is what you have a dozen times first" is referring to the letter 'T', which is the first of all 12 lines of this part of the puzzle (Xenocacia)

4. "This should be one letter that stands for you." - The letter "U" stands for you (stack reader)

HINTS

1. Let's call the first blockquote a "#1", the second one a "#2" and the third one a "#3".
   The first six lines of #3 is written in form of "what to do with #2 using #1", "what comes out (let's call it #4)", "what to do with #4 using #1", "what comes out (let's call it #5)".
   The other half is some manipulations on the #5 to get the final answer.

2. Every "ME" in this puzzle (i.e. "My name" in 3rd line) refers to some real world existing object described by the 1st sentence of the 1st blockquote. It is an engulfing whirlpool which is third in the world radially (some google/wikipedia search most probably required). The name is to be used (3rd line) the same way some French guy (who is dead now and knew some ciphers) used to on the current message (which is aments caphar) to get another one.

Answer 1

Following on from Gareth's answer, the thing that makes you so strong is

CURRENT

Gareth left us with

CAVERN TERRAE

The single "r" is present but in vain,

CAVERN TERRAE = CAVEN TERRAE

Two first, two second, and two first again.

CAVEN, then TERRAE, then CAVEN = CARREN

The last thing you have to append here rests.
This is what you have a dozen times first.

T starts a dozen lines, append it to get CARRENT

There is something strange. Why "a"? Any clue?
This should be one letter that stands for you.

Replace "A" with U (stands for you) to get CURRENT

Answer 2

You are

the Corryvreckan whirlpool

which is

the third-largest ("radially third") whirlpool in the world.

So what makes you so strong, at least according to Wikipedia, is

"strong Atlantic currents and unusual underwater topography", and in particular a pyramidal underwater basalt pinnacle.

After getting to

AMENTS CAPHAR

as described in Sid's answer, we can then

use "my name" CORRYVRECKAN after the fashion of the "dead French guy" Vigenere

to get

CAVERN TERRAE

which is to say,

a dark place underground followed by the lunar highlands, which tend to be the bright parts.

It looks like it's time to consider the second stanza now, which I haven't done yet.

Answer 3

Partial answer:

The first line of puzzle text and first hint refer to a keyboard: QWERTY with ASDFG below. Still working on the others.

"This is what you have a dozen times first"

Referring to the letter 'T', which is the first of all 12 lines of this part of the puzzle

Answer 4

Partial answer

This should be one letter that stands for you.

The letter "U" stands for you

The last thing you have to append here rests.

This might be a stretch but perhaps you have to append a "Z"(zzz for sleeping sound in cartoons)

Answer 5

PARTIAL ANSWER

Ok, The OP has clarified that I am on the right track

Using a QWERTY keyboard (As found by @Xenocacia), And shifting the the cipher text by one letter to the right and converting "P" to "A', the cipher text decodes to "Aments Caphar". Caphar is an ancient term for toll or duty imposed by turks on Christian merchants. That is what the first line of the riddle says. Aments refer to a mentally-deficient person, thus, the mentals collecting tax.