Knights Contract

This achievement is called: True Peace at last
Its the achievement for defeating the final boss of the game. It has two forms in the first form its easiest to capture it with the trap spell and unleash your fury at it. After it lost some health it will start to crate a shield under itself and here comes the little bit tricky part and you hopefully collected the Witchcraft Elisabeths Fang (because it frees itself now way to fast from the trap to hit it at all). With Elisabeths Fang however this one it is easy going.
Just lock the boss on evade and wait until it land when it does immediatly unleash Elisabeths Fang to deal massive damage. That should end the 1st form the QTE´s are as follows (thx Glennmasamune): B (mashing) / UP / Y

In its 2nd form it attacks just like in the 1st one it learned only 1 new move to throw rocks at you just do the same with Elisabeths Fangs like in Phase one and 2 hits should be enought to beat it after that surprise suprise an new set of QTE`s: LEFT / X / Y / B

It has been done by me on normal difficulty. If there are any other ways to defeat it please let me know.

For Hexen Knight or Witchslayer difficulty,I found a fast way to beat her.Immediately lay down a Lvl3 Collis trap.Use a Lvl3 enoch hammer to knock her down into the trap.Hit her with a Lvl3 Mars Lance,then follow it up with a Lvl3 Vladds impaler.Usually doing this procedure 2x's (possibly 3) will lead right to the QTE.
It also works great for her 2nd form.Just in a different order.The Lvl3 Mars lance gets rid of the yellow shield,then you can knock her down into the trap with enochs hammer,then hit her with the impaler.