Mori no Majuu ni Hanataba wo(2012)

Mori no Majuu ni Hanataba wo

In a world dominated by swords and magic, Cleo lives his lonely life where he believes painting is his sole purpose to life. Since Cleo was born in a noble family, he must prove himself worthy to become the family's successor by participating in a certain trail. As he enters the forbidden forest, Cleo encounters a beast that is half human and half plant. After being easily captured by the beast that resembles a human girl, Cleo plans his escape by attracting the beast’s interest and keeping Cleo alive. Out of his expectations, the time they spent living with each other made him feel unbelievably relieved. However their calming daily life did not last very long…
A human and monster love story. A heartwarming fantasy tale.

(Source: Shogakukan, translated)