Avalokiteshvara (Quan Thế Âm), the one who listens
The name Quan Thế Âm means "one who listens to the sounds of the world". In the Mahayana tradition this Bodhisattva stands for compassion: hearing the cries of beings and coming to help.
One story says that as Quan Thế Âm was about to step through the door of liberation, a cry of suffering rose from the human world. The Bodhisattva paused and vowed to remain until every being was free from suffering. From that vow, the figure appears in many forms, according to where help is needed.
In Vietnam the Bodhisattva is often called Quan Âm or Phật Bà. Statues stand or sit on a lotus seat, holding a vase of water and a willow branch. The water stands for coolness and relief, the branch for gentleness.
Tellings of Quan Thế Âm vary a great deal, so you may hear them told differently. What they share is a heart that listens and cares. See also the altars and the Avalokiteshvara days.