There are many types of youkai with extremely varied powers. Some races have a great number that are all categorized under a certain name, while others can be as few as a single member.

These unique youkai are not called by whatever individual species they may be, but simply "youkai."

Many of the youkai in Gensokyo fall into this "youkai (*1)" section.

Rarely if ever is there any commonality in their appearance, ability, character, danger level, or times and places of activity.

Just about the only thing in common between youkai is that they attack and prey upon humans.

There are definitely exceptions, but many fall towards this trend.

*Youkai have longer lifespans than humans.

*Youkai have stronger bodies than humans, so even if they're split into five parts, they heal right away.

*Youkai are more easily affected by belief than humans, and as a result spiritual damage can cause fatal wounds.

*Youkai generally do not move in groups.

*Youkai only think of themselves.

Youkai are the most dangerous enemies to humans.

However, since they are rather varied, one must be informed of each of their traits before heading out to exterminate them.

1: It might be confusing, but youkai as a race is similar to the "Others" section of a graph. I suppose there are quite a few graphs where "Others" is the largest category.

Humans have no greater enemy than youkai.

Youkai attack humans for food.

However, most do not attack when they are full and satisfied.

If the human population drops, youkai will face trouble as well.

They do not eat only humans, but animals, birds, fish, vegetables, fruits, alcohol and other things humans normally eat.

Still, they consider humans a delicacy above all else.

They steal crops and livestock as well.

This is also serious problem.

Unless one thoroughly trains in fighting against them, youkai extermination is difficult.

Youkai have a history of being physically stronger than humans, and trying to fight them may quickly end up as feeding them.

However, the reason most youkai attack humans is because they need prey.

That's why one should offer something else to eat in place of themselves.

Offering a cow will save you from being attacked for a while.

There are many that have a strong sense of duty, and will befriend those who do not turn against them.

But exterminating youkai is a different story.

Humans regularly perform exterminations, but this is a custom passed down from ancestors.

In Gensokyo, humans must exterminate youkai (*2).

There are those that specialize in youkai extermination.

For example, the Hakurei shrine maiden is the most well-known specialist.

In extermination, one does not use weapons that cause physical damage. Weapons with an "origin" are more preferable.

Youkai are weak to spiritual attacks such as names or traditions.

2: It is said that the balance of Gensokyo will crumble if they do not.