I can't seem to find out what this word means. I know Reno says it a lot when he attacks somebody, is it just like a war cry? Because I can't seem to find any translations for this word ):

I think it's actually just a random yell, like "aargh" or the suchlike.

or Ayaaaaaaaaaaahhhh

It's just what he wrote in the subtittle for his warcry

its basicly wut the japs say b4 they sock some1 ^_^ (no joke) (i said it myself many times)

I actualy found myself saying that today. Can't really remember why, but it sounds cool.

i agree...very cool but i dont hit people so i wont have to say it...im a good little boy you see