Polar Bunny

Rock Barrier, a polar bear who rules over the Arctic snowfields surrounded by snow and ice. One day, he picks up Robbie, a black rabbit who was found with lost memory in the South Tower. As Barrier, who is always cool and rational, becomes more obsessed with Robbie, the sleeping nature of animals begins to awaken as the polar night approaches... Rock and Robbie are no exception.

(Source: Lezhin, translated)

Note: Chapter count includes three side story chapters.