In Denmark, you may not acquire, possess, carry or use firearms, knives or other dangerous weapons, except in specific cases with particular police permission. It is also illegal to use self-defence sprays such as CS gas in Denmark.
Knives in public places
You may carry a knive in public places if you have a "recognized professional and/or leisure use" - e.g. if you carry it in relation to work or sport.
For pocket knifes this "recognized professional and/or leisure use" is different from normal knives. It is legal to carry a pocket knife one day if you are going on a picnic, but it will be illigal to carry the same knife when going out at night or in public places with many people.
However, Denmark is a very safe country and it is extremely uncommon that people carry knives.
Weapons for hunting or competition use
If you live in an EU country and have a European firearms licence, you do not need special permission to use your weapon in Denmark for hunting or target shooting. If you live outside the EU, you can use your weapon for hunting or target shooting if you have a gun licence from your home country or a statement from the authorities that such permission is not needed.
It is against the law to bring fireworks into Denmark, as a private citizen.