A New Champion is approaching to League of Legends: PoppySquare Poppy. From Steve 'Pendragon' Mescon's words:

Prepare yourselves. The tiny but mighty Poppy has joined the League of Legends! This compact little warrior packs one mean punch with her mighty hammer, Whomper. Boasting a powerful set of abilities, Poppy is ready to pulverize anyone who thinks it funny to make a short joke.

She will be included in the game for the next patch.

Source Riot Games