Article: To get Wario, you need to have Luigi unlocked. His ability to turn invisible lets you get to where Wario is hidden. If you have not unlocked Luigi, read our article on how to unlock Luigi. You can't get Wario until you can get to the second highest floor of the castle, and you can't get there until you've beaten Bowser a second time. When you defeat him, you'll get the key to the upper floors of the castle.  The first Bowser level is "Bowser in the Dark World." It's behind the star door on the main floor of the castle. Grab Bowser's tail and throw him into the bombs at the edge of the arena to win! The second Bowser level is "Bowser in the Fire Sea." To get there, you need to fall into the hole in the floor in the same room as the blue portal to Dire, Dire Docks. Once you get the first star in Dire Dire, Docks, the portal will move back, which lets you fall into the hole. Be careful — Bowser has learned a teleportation move and the entire arena will shift from side to side as he jumps around. From the castle's front lobby, run up the stairs and open the big door with the lock on it. This will lead you straight to the second floor. On the second floor, look for a door with a star on it, but no number. If you're in the right place, you'll be in a room with several different paintings and a large mirror on one wall. If you're in a cross-shaped room with three copies of the same painting in different sizes, you're in the room for Tiny-Huge Island. Leave and try the other door. This power-up is in the mirror room with you. Luigi should now be invisible. You should now be on the other side of it! This is why you needed Luigi — Mario and Yoshi can't get here. This will take you to a secret area where you can unlock Wario. This level is fairly short, but you still need to make it to the end to have a shot at unlocking Wario. Use the instructions below to make it through in one piece:  Go down the slide to the lower platform, then cross the gap to the next platform. Hop onto the moving metal platform. Hop off onto the ledge. Turn right and go over the gap. You'll be caught by a gust of air and lifted up. Land and cross the two platforms to the ice pillars. Continue until you reach the other side. Climb to the top and go into the hole to reach the boss for this level. The boss for unlocking Wario is Chief Chilly. To beat him, you need to knock him into the water three times. Avoid falling into the water yourself — like lava, it will damage you on contact.  Chilly is fought basically the same way you fight the Bullies in the lava level. You can walk up to him and punch him, but this makes it easy for him to hit you. Each time you push him into the water, he gets weaker. If you're confident, you can use the tackle (attack while running) to knock him back far. Once he's hanging off the edge, knock him into the water with a normal punch.  Once you have beaten him, grab the key that he drops. This is the room downstairs where you originally switched to Luigi for this challenge. Enter the door with a W above it. You'll use the key you got from Chief Chilly. Congratulations! You've unlocked Wario.

What is a summary?
Make sure you're already playing as Luigi. Make sure you've beaten Bowser twice. Go to the second floor of the castle. Go to the mirror room. Get the Power Flower. Walk through the mirror. Jump into the Wario portrait. Complete the level. Defeat the boss. Switch to Wario in the character change room.