um-u can do it as a custom ability if that is what u mean-the base spell itssle fis onyl supposed ot hit once. but if u need to know how to do ability multiple times i think i know how to do it.
go to where u edit abilities.
make the base spell starfall and make the icon fan of knives. then somewhere it should say what the spell should actually do-like heal unit or damage unit or give a buff. make it do damge equal to knives damage. then make the animation as fan of knives. if there are like 5 waves of stars then it should cast fans of knives 5 times. or u can lower the mana cost and cooldown period of the spell so u can just keep hitting "fan of knives".
but if u make it starfall it will make it as a unltimate ability. to get it as a reg ability, to make as reg ability..uh..dammit..who u do it..
um...i trhink there is a way to link 3 spells together to make then reg spells. just make the spell 3 times and there shoudl be somekind of link to put em together.
or u could possibly put the spell on auto cast if u edit it and lower cooldown period. i did all kinds of stuff with editor but its been liek a year since i was editor-i dont even have wc3 installed anymore. jus wait till i get a new comp-just wait....