The Kinslayer has always been a favourite Nightwish song of mine, and have always loved the intro. This arrangement has pretty much all the Keyboard parts of the original song, along with other instruments to make it sound more complete. This does make it harder to play, so you can just choose to play along with the original song just the Keyboard melodies. (However, keep in mind that I did skip out on a few of the long chordal passages in favour of a more exciting guitar or vocal melody.)
Notes:
Bars 17-32, 79-86: This chromatic bass line is taken from the bass guitar. It can be quite hard to play in conjunction with the keyboard's chords, but it does make the piece song more complete and closer to the original song.
Bars 73-75: This is the vocal melody and can be quite hard to play at the same time as the bass rhythm, but it definately sounds good if you can get it correct.
Bar 87: This last note is actually an explosion in the real song, which is quite hard to notate on a piano. :P You could leave it out instead of playing a bottom E like I notated.