|This is real.|
In the original story, Donald Duck accidentally received ownership of an abandoned villa called the "Vila Rosa", which was meant for his cousin Gladstone. Donald and Gladsone didn't care enough to fix the mistake. While touring the villa, Don discovered the diary and suit of the 19th-20th century gentlemen thief / vigilante Fantomius. Donald learned of Fantomius' method of hiding his alter ego: pretending to a harmless loser by day and getting revenge at night. Angered by Gladstone (who is more privileged than Donald) mocking him, Donald became the gentleman thief Paperinik using Fantomius' modus operandi. He stole $1,000,000 from Scrooge McDuck and framed Gladstone. Despite Gladstone managed to recover the money thus pleasing Scrooge, Donald felt filled and declared he only just began.
Originally, Paperinik was an antihero similar to Fantômas (whom Fantomius is clearly based on) and Diabolik (who he is probably named after). Paperinik completed illegal crimes to get revenge on society for his grievances (usually involving his uncle, Scrooge). To achieve this, he used gadgets Gyro Gearloose gave him.
Realizing the making one of the iconic Disney heroes a villain wasn't a good idea, the writers started to change this. As such, he became a more Batman-like hero. He used gadgets and nonlethal weapons. In face, he even had his own version of the Bat-Signal. Gyro Gearloose became his most important ally. These stories tended to be more light-hearted than the vengeful originals. There were several failed attempts to revamp the series.
Paperinik had different names in different counties. These include Superpato (Brazil), Superdonald and Fantomerik (Dutch with the first being the current name), Stål-Kalle (Sweden), Taikaviitta (Finland), Super Paja / Super Donald (Yugoslavia), Φάντομ Ντακ / Phantom Duck (Greece), Fantonald (Norway), Superduck (UK), PK (Italy and an USA video game), Superkwęk / Super Quack (Poland), Duck Avenger (USA), Fantomiald (France), Patomás (Spain), Phantomias (Germany), Stálöndin (Iceland) and Stålanden (Denmark). Stålanden may or may not be actually translatable into English (Translate Google gave me odd results (such as "[S]teel Other", "the [S]teel [W]ar" and other nonsensical things).