Taira no Shizuka (平らの静か) is a fictional character, but he has some real life counterparts. In The Accidental Samurai, Shizuka is a skilled assassin hired by Saneyori to assassinate the Emperor. The plot is foiled, however, by Bar Asher and the Kunai-Kyo. There are accounts of spies and assassins in the Heian era, most famously Hasetsukabe no Koharumaru, whose exploits and sad end are documented in the 10th century chronicle called the Shoumonki. Some believe these early spies and assassins were precursors to the 15th Century Ninja, but beyond the fact that both had great skills at camouflage and fighting, the link is not clear.
As with most of the fictional characters in the book I was careful in naming Shizuka. As you know from previous entries, Japanese names at that time (and today) begin with the family or clan name, in this case Taira (平ら), and end with the given name, in this case Shizuka (静か). The term “no” (の) is similar to a possessive or connective link, and means essentially “of” in this context. The word Shizuka means quiet, and therefore Taira no Shizuka (平らの静か) essentially means Quiet of the Taira family or clan. The Taira clan was a powerful clan at that time, and became even more powerful in subsequent centuries. Like the Minamoto, the Taira were often associated with military prowess. My intent was to imply he is fleet-footed and silent. Please note in modern Japanese names the “no” is generally not used so it is: family name, given name.