Fable II

You unlock chain attacks when you upgrade Brutal Style to level 3. If you time your attacks correctly, you'll see a blue streak follow your weapon. Get several chain attacks in a row, and the achievement will pop. Your hits don't need to connect with enemies, you can feel free to find an open area and try as many times as you need just swinging in the air.

I was having a lot of trouble getting the rhythm right. But I came across a great suggestion: try using a metronome.

http://www.metronomeonline.com/

I used the Hammerthyst, maxed speed, with 96 BPM. Just hit X every time you hear the noise. You can do this with any weapon, and don't need to max speed, but the tempo will vary and you'll have to find another number that will work for you.

I upgraded my speed used the Hammerthyst and I still couldn't get it.
What worked for me was what is mentioned in the video below. Rhythm, I found tapping my x button as a steady rhythm worked, the trick is you have to find the right speed for you, try going slower or faster until you see the blue arc from your swing, once you track to the right speed lock it in and just keep at it. Also find a clear spot where you can swing but don’t move forward, like a ledge or something. And FYI I actually ended up using my speedier master cutlass instead of Hammerthyst weapon, I think I was just tapping too fast with the slower Hammerthyst.

Good luck and be patient.

Having your Speed at around level 4 should be better for getting this achievement, along with a slower weapon (axe or mace) to aid in the timing (slower swings). Make sure your Brutal Styles is also level 3 so you can do chain attacks.

Get yourself into an open area (an uninhabited one if you don't want to scare people) and begin swinging. You'll have to press X at the peak of the previous swing for it to count as a chain attack.

You can visually see the difference between a regular swing and a chained swing by the colour: chained swings leave a blue trail after each one. Do this five times in a row and the achievement is yours.

You need to level up Skill > Speed to level 5 and then you'll need to level up Strength to at least Brutal Styles 3.
Then find an open empty area.

This requires is a chain of 5 chain attacks. A chain attack is an attack that rolls off the last attack, so pressing X at the peak of the previous swing will unleash a chain attack, which is indicated by the blue swing. You need to chain 5 of these together, one after another.

-note that the video is not by myself-

i was having all kinds of problems trying to get this, until today. what i did was i used the dalchi sword. i know all the other guides say to use a slow weapon, but i couldnt ever get a single blue line using those, let alone five. i went to the top of the mountain in bower lake where you exit from the guild cave. i positioned my guy against the edge, so that he wouldnt move around all over the place. i tapped x, lifted my finger up and counted to one x, then tapped again. this worked out for me. just give yourself about one to two seconds before hitting the x button again.

First, be sure you have the Brutal Styles at level 3 which is chain attacks. Then use any weapon you liked for example I used a the Daichi and it worked.

You have to press the X button at the end of your swing. Each time you press your character will accelerate his motion. Don't forget that you'll need to press the button faster and faster. When you have some blue trail continue to accelerate and the duellist achievement sould pop out in you screen

Note: I don't know which level you must be in speed to do it but I know you need to the level 3 in Brutal Styles in the Strengh category

I tried to do this with various weapons and suggestions but could never get the timing down. While trying to get some co-op achievements with the second controller, it seemed to me that the window of opportunity for the combo is larger. I just pressed X on both controllers and nailed that achievement in one shot, no particular rhythm, it just unlocked and really surprised me how simple it was. I noticed also that both weapons had much more consistent "blue" swings.

Like Honra mentioned in his video you do not need to be fighting any enemies to get this achievement.Just make sure that your under SKILL you have your SPEED maxed out which is 5 stars.Make sure you have nothing blocking your path such as a wall,tree,rock.Choose a clear path.Then,between every swing you make with [X] you have a pause with your weapon.[X],pause,[X],pause,[X],pause,[X],pause,[X].Be patient and get feel for it.Good luck.

The higher the upgraded speed you have, the easier it is for you. Grab any good sword, and swing it with a rhythm. You'll see a blue light coming out of it when you are doing it correctly. Maintain this blue light for around 8-10 swings, and it should unlock. Might unlock at fewer swings.

Or you could use the guide below:

I've helped 100+ unique players with achievements in Fable II and I have no intention in stopping. Players join my game, and I will unlock the achievement within a very short period of time after you've joined. The procedure is swift and requires nothing from you except that you have both of the DLCs installed. This can be either the free versions or the premium ones.

As long as this achievement is up, I'm offering the help. Simply send me a friend request, and a message stating the reason you've added me, and I'll help you the next time I'm free. Please don't send me messages asking me when you can get help, as I always keep in mind my "businesses" and I won't forget about you. And because my friends list is set to only have certain people, I can therefore not keep you on my friends list, unless we've agreed that I will.

Now, go ahead and send me those messages! I'm eager to help out :)

Unlock this, and every other Fable II achievement in the Fable II Walkthrough