Castillo, known as Cielo Castillo (シェロ・カスティロ Shero Kasutiro, lit. "Sky Castle" in Spanish) in Japan, is DenTech City's first theme park, which has its grand opening during the events of Mega Man Battle Network 4. It serves the purpose for many events, including the NetBattle tournament known as The Eagle/Hawk Tournament. Attractions include Solar Boy Django, Halberd Princess, Wizardog, and TinMan. ShadeMan.EXE causes chaos in the area, but he is deleted by MegaMan.EXE.
Entrance (エントランスゲート Entrance Gate in Japan) has the entrance and exit of Castillo, where tickets are sold. Near the entrance is a huge fountain, a Cafe Plaza, and a Metroline station that sells park goods.
Ticket Comp is the Cyberworld from a ticket machine in the Entrance.
Center Square (ちゅうおうひろば Chuuou Hiroba, CenterSquare) is the park's central square. In front of the entrance is a map of the park. In front of the entrance is the main attraction, Princess Halberd's castle, where the Eagle/Hawk Tournament is held. To the right is the Mel Square and to the left the park's exit. Other rides include "The Magnificent Storm - The Ride" (レネチアのあらし ザ・ライド lit. "Renice's Wind - The Ride"), a water ride featuring Wizardog, "TinMan Jungle - The Ride" (ブリキング・ジャングル ザ・ライド lit. "Bliking Jungle - The Ride"), a roller coaster whose setting has guests driving a truck in the jungle TinMan lives, a shop that sells gifts such as candies and toys of popular characters like "Uncle Andre" (オンドレじいさん Ondore Jiisan, "Grandpa Ondre"), and a stand that sells snacks and has a jack in port to Castillo's homepage.
Castillo HP, known as Cielo Castillo's HP (シェロ・カスティロのHP) in Japan, is the park's homepage, accessed from the snack stand near Princess Halberd's castle. It has a castle motif and contains a Chat BBS and a shop selling Navi Customizer programs.
Mel Square (MelSquar), known as "Märchen Square" (メルヒェンひろば Meruhyen Hiroba) in Japan, is a square with a Restaurant, a Photo Studio, the Vampire Manor, an ice cream stand, and a decoration showing a scene. A man sells the Sub Chips Full Energy, Lock Enemy, and Unlocker.
In the Red Sun version, the scene is from Pater Pon (ペーターポン based on Peter Pan), showing the titular character in the ship of the pirate captain Pook (プック) and the pirate Tonbi (トンビ). In the Blue Moon version, the scene is from Tydamic Ghost (タイダミック・ゴースト Taidamikku Gōsuto), where Mr. Quesola (ミスター・ケサオラ Misutā Kesaora) tries to save his wife Cornesso from Baron Sargasso (サルガッソ Sarugasso) and his pirates.
StandComp is the Cyberworld of the ice cream stand in MelSquare. It contains one HP Memory.
Waiting Room (ひかえしつ Hiekashitsu, WaitingRoom) is a luxurious room inside Princess Halberd's castle where the Eagle/Hawk Tournament participants wait for their next match. The room contains a board showing the tournament's participants, paints, statues, and chairs with a code for Mega Man Battle Chip Challenge: "Entry Name: DEX FD★3-3JW1-PS★V-♦01♦-♥6R♣-1J32".
Air Stadium (くうちゅうスタジアム AirStadium) is the stadium above Princess Halberd's castle, with a NetBattle machine used in the Eagle/Hawk Tournament.
Castillo NetBattle Machine Computer
Castillo NetBattle Machine Computer (CastNBMComp), knwon as Cielo NetBattle Machine's Computer (シェロＮＢマシンの電脳) in Japan, is the Cyberworld from the Air Stadium's NetBattle machine, where to Mr. Progs are exercising.
Vampire Manor (VampirManor) is the park's haunted attraction, featuring Solar Boy Django and Dracky. A ghoul contains a lotto number written on its forehead, 14769745, and a Gun del Sol 1 G can be found in one of the Django statues. At a later point in the game, Ozuma Kantoku can be found here, where he gives a hint to the Lotto Number that gives the Gun del Sol EX.
- ToyRoboComp - The Cyberworld from the park's four robots.