I'm having some issues with arguments, particularly this class. For this class, I get 4 errors that tell me " RpgTutorial does not contain a constructor that takes 1 argument.

Code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace RpgTutorial
{
    class MainWorld
    {
        List<Character> Monster;
        DataHandler data = new DataHandler();
        Hero myhero;
        string choice;

        public void Mainworld(Hero hero, List<Character> monsters)
        {
            do
            {
                Console.Write(@"You are in a valley, not far from the town of Zalgalax.
                                        Where do you wish to travel?
                                        _____________________________
                                       (NW) (N) (NE)
                                       (W)       (E)
                                       (SW) (S) (SE)
                                       (Exit)
                                        _____________________________
                                       ");

                Console.ReadLine();
                choice = Console.ReadLine();
                choice = choice.ToUpper();

                switch (choice)
                {
                    case "NW":
                        Northwest northwest = new Northwest(myhero);
                        break;
                    case "N":
                        North north = new North(myhero);
                        break;
                    case "NE":
                        Northeast northeast = new Northeast(myhero);
                        break;
                    default:
                        Console.WriteLine("I'm sorry, I didn't understand that.");
                        return;

                }

                int setnumber = 1;
                Random rand = new Random();
                int battlechance = rand.Next(1, 100);

                if (battlechance >= setnumber)
                {
                    Random randtwo = new Random();
                    int gibblychance = 10;
                    int monsterchance = randtwo.Next(1, 60);
                    Console.WriteLine("Suddenly, a wild monster appears!");

                    if (monsterchance == 1)
                    {
                        Monster.Add(new Zombie());
                        Monster.Add(new Zombie());
                        Monster.Add(new Zombie());
                    }

                    if (monsterchance == 2)
                    {
                        Monster.Add(new Borg());
                    }

                    if (monsterchance == 3)
                    {
                        Monster.Add(new Garryxx());
                    }

                    if (monsterchance == 4)
                    {
                        Console.WriteLine("You've been attacked by a tribal raiding party!");
                        Monster.Add(new Barbarian());
                        Monster.Add(new Barbarian());
                        Monster.Add(new Mage());
                    }

                    if (monsterchance == 5)
                    {
                        Monster.Add(new Slime());
                    }

                    if (monsterchance == 6)
                    {
                        Console.WriteLine("A vicious warrior of Gorox appears, a Gorox Paladin!");
                        Monster.Add(new GoroxPaladin());
                    }
                    Battle battle = new Battle(myhero, Monster);

                }
            }
            while (choice != "E" && choice != "e");
            Console.WriteLine("Press enter to continue....");
            Console.ReadLine();
        }
    }
}


This is my maingame class, another class that gives me an error, saying that "Mainworld does not contain a constructor that takes one arguments".

Code:
using System;
using System.Collections.Generic;
using System.Text;

namespace RpgTutorial
{
    class MainGame
    {
        List<Character> Monster;
        DataHandler data = new DataHandler();
        Hero myhero;
        Battle battle;
        string answer;

        public MainGame()
        {
            Console.WriteLine("Welcome to the world of Zalgalax!");
            myhero = new Hero();
            Hero.Initialize(myhero);
            Monster = new List<Character>();
            BasicGameLoop();
        }
        void BasicGameLoop()
        {
            do
            {
                Console.WriteLine();
                Console.Write(@"
What would you like to do?
_____________________________
(W)orld
(F)ight
S(T)ore
(I)nn
(V)iew
(L)oad
(S)ave
(Q)uit
_____________________________
F,S,I,V,L,A or Q?");
                Console.WriteLine();
                answer = Console.ReadLine();
                Console.WriteLine();
                switch (answer)
                {
                    case "W":
                    case "w":
                        MainWorld mainworld = new MainWorld(myhero);
                        break;
                    case "L":
                    case "l":
                        data.Load(myhero);
                        break;
                    case "S":
                    case "s":
                        data.Save(myhero);
                        break;
                    case "T":
                    case "t":
                        Store store = new Store(myhero);
                        break;
                    case "I":
                    case "i":
                        Inn.Sleep(myhero);
                        break;
                    case "v":
                    case "V":
                        View.PrintStats(myhero);
                        break;
                    case "F":
                    case "f":
                        string done = "";
                        do
                        {
                            Console.Write(@"
Which monster do you want to fight?
(S)lime:
(Borg):
(B)arbarian:
(M)age:
(Z)ombie:
(G)arryxx:
_________________________");

                            Console.WriteLine();
                            string choice = Console.ReadLine();
                            
                            if (choice == "g" || choice == "G")
                            {
                                Monster.Add(new Garryxx());
                            }

                            if (choice == "Borg" || choice == "borg")
                            {
                                Monster.Add(new Borg());
                            }

                            if (choice == "S" || choice == "s")
                            {
                                Monster.Add(new Slime());
                            }

                            else if (choice == "B" || choice == "b")
                            {
                                Monster.Add(new Barbarian());
                            }
                            else if (choice == "Sharkkill" || choice == "sharkkill")
                            {
                                Monster.Add(new Sharkkill());
                            }

                            else if (choice == "M" || choice == "m")
                            {
                                Monster.Add(new Mage());
                            }
                            else if (choice == "Z" || choice == "z")
                            {
                                Monster.Add(new Zombie());
                            }

                            else
                            {
                                
                            }
                            Console.WriteLine("Would you like to fight more monsters?");
                            Console.WriteLine();
                            done = Console.ReadLine();
                        }
                        while (done == "Y" || done == "y");
                        battle = new Battle(myhero, Monster);

                        if (myhero.CurrentHealth <= 0)
                        {
                            Console.WriteLine("Your game is over!");
                            continue;
                        }
                        else if (myhero.fled == false)
                        {
                            int gold = 0;
                            int experience = 0;
                            foreach (Character monster in Monster)
                            {
                                if (monster.fled == false)
                                {
                                    experience += monster.Experience;
                                    gold += monster.Gold;
                                }
                            }
                            Console.WriteLine("{0} gets {1} gold and {2} experience"
                                , myhero.Identifier, gold, experience);
                            myhero.Experience += experience;
                            myhero.Gold += gold;
                            Monster.Clear();
                            Console.WriteLine("Press enter to continue....");
                            Console.ReadLine();
                        }
                        else
                        {
                            myhero.fled = false;
                        }
                        break;
                    case "Q":
                    case "q":
                        Console.WriteLine("Goodbye {0}", myhero.Identifier);
                        break;
                }
            }
            while (answer != "Q" && answer != "q");
        }
    }
}
I'm trying to make it so that when the user selects case "w" in the MainGame class, he is taken to the MainWorld class where he can choose to go to the North, Northeast and Northwest classes, and randomly enters a monster battle.

What am I doing wrong? Am I missing brackets? Is there a broken loop here? The code won't compile properly with these constructor errors getting in the way.