Shadow Hero is out of Sookie (Casino Prince), a four-time winner whose victories include the Gr.3 Glenlogan Park Stakes in Brisbane. She was also placed in the Gr.3 BJ McLachlan Stakes, the Listed Canterbury Classic and the Listed Mode Plate. Sookie has had three foals to race, two of them winners.

Second dam Purple Blood (Encosta de Lago).

Third dam Victory Vein (Mr Henrysee) was the champion juvenile filly in Australia in 2001-02. Her wins included the Gr.1 Sires' Produce Stakes, the Gr.1 Champagne Stakes and four Group 2 races, the Silver Shadow, Silver Slipper, Magic Night and Tea Rose Stakes, and she also earned placings in the Gr.1 Golden Slipper and the Gr.1 Flight Stakes.

Since Shadow Hero, Sookie has produced Lady Grazier (Not A Single Doubt), a 2017 filly with one start, plus a filly by Pierro born in 2018. Snitzel covered her last season.