Hello 'amigo'
Well, assumming you have a grf file for you server and the kRO client. If you desire change graphically the effect, you can edit the files on the folder:
► and search for the files:
rk_enchant.tga
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also the files on:
► The files:
rk_enchantblade.spr
rk_enchantblade.act
But if is nothing graphically, if you want to make a something different, besides the custom files or original require a SOURCE CODE EDIT.