Do ranger class features apply to only your favored enemy?

Question

I have a question to the Ranger's Hunter archetype features.
At 3rd Level I got the feature "Hunters Prey" and chose "Colossus Slayer." From the description (PHB p. 93):

Colossus Slayer.
Your tenacity can wear down most potent foes. When you hit a creature with a weapon attack, the creature takes an extra 1d8 damage if it's below its hit point maximum. You can deal this extra damage once per turn.

From my understanding I can deal this to every creature if it's not on maximum hit points.

What use has then the favored enemy? I didn't find anything where abilities only apply to favored enemies. Is this Colossus Slayer ability only usable on creatures which are my favored enemy, or is the favored enemy just for roleplaying?

Answer 1

These features work against all enemies. There is only one feature that specifically calls out that it only works against your favored enemies: your 20th level capstone ability Foe Slayer

However, there is an advantage you have against your favored enemies, which is directly in the text for Favored Enemy itself:

You have advantage on Wisdom (Survival) checks to track your favored enemies, as well as on Intelligence checks to recall information about them. When you gain this feature, you also learn one language of your choice that is spoken by your favored enemies, if they speak one at all.

So really what it comes down to is that you know how to find your favored enemies and to understand your favored enemies really well.

But your ability to kill stuff doesn't discriminate, so you can stick your sword(s) in any opponent equally. (Until 20th level, anyway)