Rakka is the central character of the anime Haibane Renmei and the newest haibane to arrive at Old Home, one of the two residences for haibane in the walled city of Glie. A haibane is a being born from a cocoon with gray wings and a halo, and Rakka begins her life in this world by awakening inside such a cocoon after dreaming of gently falling through the sky accompanied only by a crow. Because of that dream, she is given the name Rakka, which means falling. She appears to be a young woman of nearly twenty years, with somewhat unkempt red hair, gray wings, and a halo, and her early days are marked by the painful emergence of her wings and her adjustment to the unfamiliar customs of her new community.

At the start, Rakka is very shy, withdrawn, and awkward, deeply confused by her new life and disturbed by her complete lack of memories of who she was or where she came from. As she settles in, she becomes more amiable and warm, showing a genuine desire to connect with the other residents of Old Home and the people of Glie. She is curious about her origins and often wonders whether her past life or family still exists somewhere, even though haibane cannot remember their pasts and are forgotten by the world they came from. She is also reluctant to burden others with her own troubles, though she willingly involves herself in helping those around her, and she tends to be emotional in the face of loss.

Rakka's role in the story is that of the protagonist whose experiences guide the narrative. The story follows her adjustment to life in Glie, her introduction to the rules of the Haibane Renmei, and her search for purpose and identity. She forms an early bond with the birds of Glie, especially crows, in keeping with her cocoon dream, and this connection recurs throughout her journey. After the sudden departure of her close friend Kuu, who disappears during her Day of Flight, Rakka falls into grief and develops dark blemishes on her wings, a condition known as being sin-bound. Her struggle with this condition leads her to a well in the Western Woods, where she finds and buries the bones of a crow, and later to an encounter with the wall surrounding the city, after which she is assigned the isolated job of cleaning tags and collecting light inside the wall.

Her key relationships shape her development. Reki, an older haibane who cares for her after her hatching, acts as her mentor and protector, and the bond between them becomes the emotional center of the story. Rakka grows from a newcomer who receives Reki's help into someone who is eventually able to support Reki in return, delivering Reki's true name and helping her confront the guilt and despair that have kept her from accepting her own Day of Flight. Kuu serves as one of Rakka's closest friends and an early guide, and the loss of Kuu is the turning point that forces Rakka to confront sorrow, forgiveness, and the meaning of the haibane's existence. She also forms bonds with the other residents of Old Home, including Nemu, Hikari, and Kana, and receives guidance from the masked Communicator of the Haibane Renmei.

Over the course of the story, Rakka develops from a confused and frightened newcomer into a source of strength and salvation for others. Her journey leads her through despair and self-doubt to a deeper understanding of forgiveness, both for herself and for Reki, and her growth culminates in her willingness to save Reki from the vision of the train that haunts her and to help her find peace. In terms of abilities, Rakka has no combat skills and relies instead on her emotional sensitivity and empathy, which allow her to connect meaningfully with others and to understand their suffering. Her wings respond to her emotional state, becoming discolored or tattered when she is distressed, and she possesses an unusual affinity for birds, particularly crows. She is also able to withstand falls with little injury, a trait that echoes her name and her dream of falling, and her emotional resilience ultimately proves to be her most defining strength.