Belarus/Russia

Belarus/Russia is a one-sided pairing in Axis Powers Hetalia/Hetalia: Axis Powers, consisting of Belarus being in love with and wanting to marry her big brother Russia. It is the only canon heterosexual pairing in the series other than Austria/Hungary, and is the only canon romantic relationship that is truly incestuous (between actual blood relations).

Russia's Big and Little Sisters
Russia introduces his little sister Belarus by saying that she is very pretty and seems to like him a great deal, but he trails off in his description of her after that. She is then shown clawing at a door with Russia shown trembling behind it, asking him if he really wants to be with "that damn bastard" and declaring that she's going to "become one" with him. A visibly crying Russia pleads with her to "Go home!"

In the next strip, Russia states that Belarus is strong-willed, but in the worst way possible. She is shown tearing out the doorknob and opening the door to chant to Russia, "Let's get marriedmarriedmarried!" Once again, a sobbing Russia cries at her to "Go home!!"

After these strips, Russia has a flashback to when he, his sisters, and many other nations all lived together under the same roof, until he was left alone. Belarus is shown to be the only nation who decided to come back to him, telling him that she wanted to stay by his side forever. Russia seemed grateful at first, thanking her, but appeared to become slightly disturbed when she followed this up with the suggestion that they get married so that they can get even closer together.

Belarus also sneaks up on Russia sitting on a bench as he's listening to France's radio show, grabbing him from behind at the end of the strip and making him cry out in presumed shock.

Other Strips
Belarus has made brief appearances in a couple of other strips, all of them by Russia's side. In the strip where Russia unknowingly sits on Canada, he is seen commenting to Belarus after the meeting about how comfortable his chair was and asking if he should buy a new one, and Belarus replying that he should do whatever he likes.

In a recent strip about the G8, Belarus visibly glares at England after he says that Russia should be disqualified as a member of the G8, and then sneezes while Canada is speaking. The link to this is http://aph.starry-sky.com/blog-entry-657-2.html

Fan Speculations
It is a widely accepted theory that Belarus's comment in Russia's Big and Little Sisters about Russia possibly liking someone else is referring to Lithuania, and that her jealousy over Lithuania being the one her brother likes was the reason for her breaking his fingers on their date. Belarus also seems to be jealous of even her sister Ukraine, looking displeased when Ukraine gave Russia her scarf.

Russia is almost always depicted in Belarus/Russia fanworks as being scared of Belarus's overzealous affection, but it should be noted that while he's unquestionably terrified of her in the published manga's strips when she tries to get him to marry her, the two brief cameos of them together in the webcomic appear to indicate that they are capable of getting along well together when Belarus isn't actively trying to force Russia into marriage.