If you are "targeting" Denmark players, you register a company in Malta and run the site from there. Check what all the danish casino sites are doing. A bunch register company in Malta to pay 15% tax on revenue instead of 45% in Denmark. They still pay tax on Denmark players with the Danish license but not taxed on other countries players at the Denmark tax rate.
Every "legal" online casino in Denmark has a license with Spillemyndigheden though. You may not be allowed to get a license with just crypto if you want to be a Danish casino, lots of rich companies avoid that license cost and Denmark - it is high license cost.
The "dodgy" way is to get the curacao, Khanawakee or Antigua license and run casino from there. Can target any country but the people behind the casino have to hide basically because those countries regulators will want to know who is offering illegal gambling in their country.
The "legal" way requires a lawyer in every legislated jurisdiction to make sure you are complying with the license requirements there. That can add up with Italy, Spain, France, UK, Belgium, Germany all having different regulatory requirements and licensing rules/costs. Then there are the US "state" licensing laws....
It is a rabbit hole once you start offering online gambling, this is why we are currently in a "fight" with an ICO that knows nothing of legislation worldwide here
https://bitcointalksearch.org/topic/m.43725038