Defensive stance pg 220

" The character makes no attacks and instead concentrates entirely

on self-defence. Until the start of his next turn, the character can

only use his Reactions to make the Evasion Reaction , but may

make one additional Reaction, and all opponents suffer a –20

penalty to Weapon Skill tests made to attack him."

Evasion pg 220

" After a character is hit from an attack, but before damage is rolled,

he can attempt to negate the hit by making a Dodge or Parry test. "

So if i take a defensive stance, can I then use Parry to evade, which if successful, grants me an automatic return attack?

And with 'step aside' and 'counter attack' talents and the granted + 1 reaction from defensive stance means i could effectively dodge once and parry 3 times?

Reaction: dodge or parry

Bonus reaction: dodge or parry

Step aside: additional dodge

Counter Attack: additional parry

Final result, I have the chance of making 3 return attacks and make myself a harder target at the same time?

So if i take a defensive stance, can I then use Parry to evade, which if successful, grants me an automatic return attack?

Yes, if you have the Counter Attack Talent.

And with 'step aside' and 'counter attack' talents and the granted + 1 reaction from defensive stance means i could effectively dodge once and parry 3 times?

You can make 3 Evades against 3 different attacks yes. Note however that Counter Attack triggers from a successful Parry and you can only perform one Counter Attack per turn.

Reaction: dodge or parry

Bonus reaction: dodge or parry

Step aside: additional dodge

Counter Attack: additional parry

The last one is incorrect, Counter Attack does not grant an additional Parry.

Final result, I have the chance of making 3 return attacks and make myself a harder target at the same time?

See above, one attack only from Counter Attack. And it is made with a -20 penalty.

Sorry my bad.... i meant wall of steel not counter attack, but BOTH would be required but I forgot the 'once per turn' bit.

If you're still around, I want to chip in:

First, terminology is important in this case. [Counter Attack] provides a potential attack per Turn. A [Round] is made up of each character's Turn, regardless of how many characters are in a battle. You may absolutely make (up to) three Counter Attacks before your Turn comes up again, since that would be another Round.

Second, keep in mind that [Wall of Steel]'s +1 Parry is from earlier games, along with its sister Talent [step Aside] which only provided +1 Dodge then. I would wager that <Dark Heresy Second Edition>'s Step Aside is meant to incorporate both into the same Talent to save experience. That would mean that Wall of Steel simply doesn't have a place in Second Edition, but your mileage may vary.

Third, remember that a Counter Attack is made with a -20 penalty, as was mentioned, and is also not a [swift or Lightning Attack]. You are more able to "not lose" if you turtle in Defensive Stance, but actually "winning" may be harder. One attack per enemy is hardly going to be lethal when it counts, even with something as strong as a Power Fist. Defensive Stance is useful, but has prominent weaknesses.

I hope my input is helpful.