The drums of Rillaboom, so famous for their role in energizing Galar's deep forests, originated as backing for Zarude's chants. The two species are closely related, diverging only in the Holocene, in a split often likened to, but not quite the same as domestication; Simisage is a more distant relative.

Zarude are fiercely loyal to their family and troop; those who were not, one surmises, became the ancestors of Grookey. Zarude resent humans for stealing their children and cutting down forests, and believe that they themselves, as fellow primates of comparable intelligence, ought to have become the world's dominant species. Although defeated on a global level, Zarude fight for their forest as if humanity's victory never occurred, and the ferocity of their resistance is often considered one factor in the decision to set aside the Wild Area as a nature preserve.

Every now and then, these pokemon have been known to raise lost or abandoned children as one of their own, who grow into emissaries to humanity. Conversely, while most trained Zarude were kidnapped as children, and became loyal to their trainer and teammates in place of their biological family, it is not unheard of for an exceptionally powerful wild Zarude to form temporary partnerships with strong trainers, ones which rarely last beyond a single tournament; it is a way to see the world outside the forest before returning home, and witness the wonders and dangers posed by human society in the era. Those who become too greedy and refuse to let their Zarude go home soon experience the limits of the loyalty a pokeball provides; they are bound to their beds as they sleep, and often must wait hours or days for someone to release them.