Well I'm doing the Man of Mystery hunt (the gilgamesh swordsman) and I've faced him already at tache spin in lhusu mines , and he ran off, now I dont know where to find him

You need to get Key to site 11 if I'm not mistaken... And you can find it in Phon coast... Just keep exploring the area and you will find him... Becareful with the enemies there... They are dangerous.