Iron Chef Optimization Challenge in the Playground CXXXII

[loky1109]

I have a question about Vow of Vengeance feat.

Choose one creature type or subtype from those given on Table 3–14: Ranger Favored Enemies, PH 47. You gain a +2 profane bonus on damage rolls against these creatures, as well as a +4 profane bonus on rolls to confirm critical threats against them.

To fulfill your vow, you must kill at least one creature of the selected type each month. When facing these creatures, you cannot retreat and you must fight until you or all the creatures of your chosen foe are killed. You can take prisoners, but they must die within 1 week of capture.

If I select Humanoid (elf) must I fight every drow I see?