Rielle

Rielle, the Everwise is a Human Wizard from Ikoria.

Description
Rielle is a wilderness sage, a whip-smart, shriveled old lady sorcerer who knows just about everything there is to know about everything. She usually wears multiple mismatched coats and scarves. Rielle met the planeswalker Vivien Reid near Lake Attayal, in Ketria, shortly after Vivien arrived on the plane. She befriended the planeswalker and shared with Vivien many of the legends and secrets of Ikoria. Rielle seems to be especially versed in the mythos surrounding the apex monsters of the triomes.

Rielle's wisdom is exceeded only by her age. Rielle herself claims to know "almost everything about almost everything on Ikoria". Vivien's only skepticism about that claim is how quickly the sage rattled off the list of things she supposedly didn't know.