Source: Horror Realms, pg(s). 41
Yamada Osa is a painter who studied the culture and settlements of numerous nations during her travels across Tian Xia. She left many paintings across Tian Xia; her ultimate fate is unknown. Those that she painted during her long stay in the town of Baakai in Shenmen captured the land's twisted energy, turning them into powerful artifacts known as Osa paintings; it is unknown if this was Osa's intention or something that happened after her disappearance.