The god who is the son of Odin and the giantess Rind is Váli.
Váli is one of Odin’s sons and is especially associated with vengeance. In the mythic tradition, he was born to avenge Baldr, Odin’s beloved son, after Baldr was killed through the actions of the blind god Höðr. Váli grew to adulthood with extraordinary speed and killed Höðr while he was still only one day old.
The sources do not consistently describe Rind in the same way. Snorri Sturluson’s Prose Edda treats Rindr as one of the goddesses, while Saxo Grammaticus’s Gesta Danorum presents her as a human princess. Calling her a giantess is therefore a less certain characterization than the stored answer’s identification of Váli, but it does not change the answer to the question.
Váli is sometimes confused with another Váli, a son of Loki mentioned in a problematic passage of the Prose Edda. The better-known Váli—the avenger of Baldr—is Odin’s son and is prophesied to survive Ragnarök.