Denkou

Denkou is a character that appears in the Astro Boy 2003 TV series. Denkou only appears in episode 4 (episode 6 in the english version) Into Thin Air (along with a brief cameo in episode 48 Journey to Tomorrow) and also appears in Akira Himekawa's manga. They also make an appearance in the Astro Boy 2004 Video Game and in Astro Boy: Omega Factor. Denkou is a robot who has the ability to turn invisble.

Biography
Before being seen onscreen, Denkou was made by Dr. Emil in his mountain laboratory. However, they were soon stolen by the gangster Skunk Kusai, who sought to use Denkou for criminal purposes. Fooling Denkou into thinking that they were playing a game called "Now You See It, Now You Don't", Skunk had the invisible robot steal from countless museums, adding to a pile of stolen treasure each day like so many other robots before him.

Denkou made their first appearance (invisibly) during episode 4, when they had stolen a golden Egyptian statue. They startled the guard and caused him to faint. Denkou, thinking that the guard was asleep, said that the floor of the museum wasn't a comfortable place to sleep and then walked off with the statue, laughing (in a friendly manner).

Denkou made their next invisible appearance at Astro's school, where they handed Alejo his backpack. Alejo soon believed that he was starting to go crazy; he then left (albiet, offscreen), no doubt with Denkou following, curious as to what was happening.

Denkou was present (but still invisible) during the history lesson for Astro's class. When the storm hit, they grabbed Abercrombie's arm for support, but wound up scaring the class, making them think they were a ghost.

Trivia

 * Denkou appears as one of the bosses in the Gameboy Advance game Astro Boy: Omega Factor. They are one of the world's strongest robots who served Shadow and is fought after North. During their battle, they will run around the arena leaving time-bombs prompting the player to chase after them. When they become invisible, the player must destroy one of the regenerators glowing in the area to disable their ability.
 * Denkou doesn't seem to have a confirmed gender, with their gender varying depending on the dub.