Introduction
Rindr is a figure, described variously as a giantess or a mortal princess depending on the source, who became, through her union with Odin, the mother of Vali, the god born expressly to avenge Baldr's murder.
Family
Union with Odin
The Poetic Edda's Baldrs draumar and other sources describe Odin seeking out Rindr specifically to father the avenger prophesied to kill Hodr, sometimes using disguise or magic to accomplish the union, reflecting Odin's characteristic willingness to go to great and sometimes ethically ambiguous lengths to secure necessary outcomes.
Later Danish tradition
The medieval Danish historian Saxo Grammaticus, in his Gesta Danorum, tells a considerably more elaborate, euhemerised version of this story, in which Odin, as a mortal king, pursues a princess named Rinda through a series of disguises and stratagems before finally winning her, a very different narrative tone from the terser Eddic sources.