Dangerous Seed (デンジャラスシード) is a vertical scrolling shooter arcade game that was released by Namco in 1989 only in Japan. In 1990, a Sega Mega Drive version was also developed and released only in Japan. The player assumed control of three separate ships operated by three separate pilots: Alpha ship is piloted by Yugo Tyrone, Beta ship is piloted by Belle Vogato, and Gamma ship is piloted by Kenny Crawford. Each ship had a different firing pattern that the player could switch between when the ships were formed together as The Moon Diver. Their mission is to quell an alien invasion spanning all of the Milky Way and destroy the aliens' headquarters: the Danger Seed.

Darius II (Persian: داريوش دوم‎) (Dārayavahuš), was king of the Persian Empire from 423 BC to 405 BC. Artaxerxes I, who died on December 25, 424 BC, was followed by his son Xerxes II. After a month and a half Xerxes II was murdered by his brother Secydianus or Sogdianus (the form of the name is uncertain). His illegitimate brother, Ochus, satrap of Hyrcania, rebelled against Sogdianus, and after a short fight killed him, and suppressed by treachery the attempt of his own brother Arsites to imitate his example. Ochus adopted the name Darius (Greek sources often call him Darius Nothos, "Bastard"). Neither the names Xerxes II nor Sogdianus occur in the dates of the numerous Babylonian tablets from Nippur; here effectively the reign of Darius II follows immediately after that of Artaxerxes I. Historians know little about Darius II's reign. A rebellion by the Medes in 409 BC is mentioned by Xenophon. It does seem that Darius II was quite dependent on his wife Parysatis. In excerpts from Ctesias some harem intrigues are recorded, in which he played a disreputable part. It is likely that Ezra and Nehemiah were alive during this monarch's reign, as it was approximately at this time that the new walls of Jerusalem, demolished during the Babylonian period, were rebuilt. As long as the power of Athens remained intact he did not meddle in Greek affairs. When in 413 BC, Athens supported the rebel Amorges in Caria, Darius II would not have responded had not the Athenian power been broken in the same year at Syracuse. As a result of that event, Darius II gave orders to his satraps in Asia Minor, Tissaphernes and Pharnabazus, to send in the overdue tribute of the Greek towns and to begin a war with Athens. To support the war with Athens, the Persian satraps entered into an alliance with Sparta. In 408 BC he sent his son Cyrus to Asia Minor, to carry on the war with greater energy. Darius II died in 405 BC, in the nineteenth year of his reign, and was followed as Persian king by Artaxerxes II.

Dark Castle may also refer to the metal band Dark Castle or the movie production house Dark Castle Entertainment. Dark Castle is a 1986 computer game for the Macintosh published by Silicon Beach Software, later ported to various platforms, where it was published by Three-Sixty Pacific. It was designed and illustrated by Mark Pierce and programmed by Jonathan Gay. Dark Castle is a platform game where a young hero named Duncan tries to make his way to the evil Black Knight, dodging objects as well as solving occasional puzzles. The game is notable for its use of sampled sounds to great effect. A sequel titled Beyond Dark Castle was released in 1987. A second sequel, Return to Dark Castle, was announced in 2000, though it was not released until March 14, 2008.