You do not need ranger to enter kinslayer. It needs two oath feats (which one is vow of vengeance, darker version of favored enemy) and then endurance and diehard. You need be 3th level ranger to get endurance feat for free.<br/><br/>As barbarian/ranger drow half-dragon you could qualify after 6th level (if taking 1st, 3th and 6th level feats devoted to other feats) and enter PrC in 7th level.<br/><br/>If you take divine ranger (complete champion) called 'Champion of Wilds' you get bonus feat in 4th level (but get no spellcasting at all). None bonus feats provided is diehard but you can ask GM allow it. So build wise barbarian 2/ranger 4 (both as complete champion divine ACF variants).<br/><br/>But as said; being 7th level barbarian also works. You just get delayed entering the PrC till after 9th level (and needs either regional or 1st level feat changed to endurance or one oath feats). Lion totem fear effect is awesome; 30'ft radius (not indicated action so guess a free action), will save DC 10 + 1/2 char level + Str mod or else mobs are shaken for barbarian number of rounds (once per day, twice at 10th level).