I want to create strategy game and sell it online but how?

  1. I’d recommend asking that question on a different AnswerHub page not related to licensing questions.
  2. It’s certainly ok under the Unreal Engine EULA to develop a strategy game.
  3. Royalty to Epic is 5% of the game’s gross revenue (after the first $3000 in revenue per quarter). So you won’t have to pay anything until you’re already making money.