Как сделать так, чтобы мой код генерировал только одного случайного монстра?

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Random random = new Random();
		int character = 15;
		int mobhp = 100;
		bool d = false;
		Console.WriteLine("You are an adventuurer.");
		Console.WriteLine("you are walking across the forest when suddenly you encounter a");
		string monsters = "d";
		
		string [] monster = {"imp", "goblin", "hobgoblin",};
		monsters = (monster[(random.Next(0, 3))]);
		Console.WriteLine(monsters);
			
			
			
			
			
		
		switch (monsters){
			case "goblin":
			mobhp = 11;
			d = true;
			break;
				
			case "imp":
			mobhp = 8;
			d = true;
			break;
				
			case "hobgoblin":
			mobhp = 15;
			d = true;
			break;
		}
		
		string hit = "attack";
		string regenerate = "heal";
		string escape = "run";
		
		while(character > 0){
		string entry = Console.ReadLine();
		switch (entry){
			case "hit":
			mobhp = mobhp - 4;
			Console.WriteLine("You attacked it!");
			Console.WriteLine("now its the monster's turn");
		Console.WriteLine("the monster attacked you");
		character = character - 4;
		Console.WriteLine("you have");
		Console.WriteLine(character);
		Console.WriteLine("hp left");	
			break;
			case "regenerate":
			character = character + 2; 
		    Console.WriteLine("you heald 2 hp");
				Console.WriteLine("now its the monster's turn");
		Console.WriteLine("the monster attacked you");
		character = character - 4;
		Console.WriteLine("you have");
		Console.WriteLine(character);
		Console.WriteLine("hp left");
			break;
			case "escape":
			Console.WriteLine("you cant run away!");
				Console.WriteLine("now its the monster's turn");
		Console.WriteLine("the monster attacked you");
		character = character - 4;
		Console.WriteLine("you have");
		Console.WriteLine(character);
		Console.WriteLine("hp left");
			break;
		}
	   if (mobhp < 1){
		Console.WriteLine ("you killed the monster and you went on your way.");
	    System.Environment.Exit(1);
	   }
		}
	}}

Что я уже пробовал:

я пробовал использовать цикл while и цикл for. ни один из них не работает.

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Console.WriteLine("you have");
Console.WriteLine(character);
Console.WriteLine("hp left");

Console.WriteLine("You have {0} hp left.", character);

Console.WriteLine($"You have  {character} hp left.");