line (naver)
A messenger smartphone application originally developed by NHN Japan, a Japanese branch of South Korean internet company Naver. Widely used in East Asian and South East Asian countries.
It has the "stickers" feature where people can buy sets of emote images, many of which are of popular anime, manga, video games, etc. Users can also make their own stickers. The application is very popular for making chatrooms for smartphone games with guild-like features in order to communicate and work together.