The narrator of "The Scarlet Ibis" has a complicated relationship with his younger brother, Doodle. Troubled by Doodle's status as an invalid and by the notion that his brother is "not all there," the narrator makes plan to smother Doodle with a pillow. These plans thankfully don't come to fruition after Doodle smiles at the narrator, causing him to realize that his brother is "there" after all.
This frustrated attitude continues as the boys grow older. The narrator tries to discourage Doodle from wanting to tag along with him by pulling him too fast around corner in his go-cart, resulting in Doodle having to cling to the sides of the cart. The narrator also takes Doodle up to the loft in the barn and shows the boy his own casket, threatening to leave him up there alone with it, much to Doodle's terror.
In his final act of selfishness, the narrator makes Doodle row their boat back to shore against the tide, which causes him to collapse in the mud. Ashamed of Doodle's failure, the narrator runs far ahead of him to punish him, while Doodle cries out, "Brother, Brother, don't leave me! Don't leave me!" The effort that it takes to try to chase after the narrator causes Doodle to die, covered in blood as red as the titular Scarlet Ibis.
The narrator, known only as "Brother," is cruel to Doodle in various ways. He wheels Doodle around much too fast and Doodle falls out of the little cart. He takes Doodle up to see the coffin that was meant to be his. He also pushes Doodle beyond Doodle's limits purely out of pride. The narrator cannot bear the thought of having a brother who is "different" when he starts school.