Person of russian nationality. Russkiye - united people of slavik origins. russkiy is usually described in a bad stereotypcal manner by envious or misinformed western cultures with double-standards. Before saying anything bad about russkiy - read the definition of redneck.
"Kto k nam s mechom pridet-tot ot mecha i pogibnet!"-Aleksandr Nevskiy. russkiy
A ratskin generally refers to a person who is displaying rat-like qualities. The term can refer to a person who is acting stingy, odd, confusing, or a person who is being short-tempered in a manner that is laughable to those observing.
It is also sometimes used as an endearing greeting.
Contrary to what some people think, the word 'ruskie' or 'rusky' was not coined during the cold war, but the crimean war in which the Ottomans fought Russia, later joined by France and the United Kingdom.
Fun fact: The Crimean campaign was the only war France won in the 19th century; the beggining of the french military victories joke