Slayer Of (3.5e Feat)
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Favored Enemy, BAB +9.
You are now a master at destroying you favored enemy. When attacking any favored enemy, increase your critical threat range by +1, and each hit does +2d6 additional damage. The addition damage factors into critical hits. See ranger for a list of creatures. If that creature type is immune to critical hits, you may now inflict critical hits upon that creature, but you lose the threat range bonus.
This bonus does not stack with "slayer" crystals.