Do you mean this one https://en.wikipedia.org/wiki/Witchking ? Sorry I have never watch LOTR Return for some reason. But I would like to share my experience on the elemental weapon effect.
First, you can find a “fire sword” video clip included in the “Customer demo reel” at about 5/6 position, which can be downloaded in Wondertouch main page. IMO, I like making the flame flies more dramatically.
https://www.geocities.jp/ifurkend/fire-sword.zip
Notable parameter setting:
* Particle type: Flame
** animated smoke texture
** Intense, Preserve coloring
** Color over life – from red to black.
*** If you don’t like the max intense white, you can
**** lower the visibility;
**** lower the number(quantity) of particle;
**** change the color tone to more saturant red.
** Size of flame particle
*** unlocked aspect of particle size
*** Size x over life – increasing
*** Size y over life – decreasing
** Motion of flame particle
*** Emission angle – 90 degree
**** requires animating adjustment to fit the video clip
*** Emission rangle – below 30 degree
*** Particles’ behavior – Align to Motion 0 degree
**** “Keep aligned to motion” – on
*** velocoty requires animating adjustment to fit the swinging speed / curvature of sword.
*** velocity variation – some