#1 Undertaker's wife Michelle McCool brought up during the course of the match
At the start of the match, when The Undertaker rode into the graveyard on his motorbike, Styles told The Phenom that he was surprised to see him here, and he mockingly asked 'Taker if The Deadman's wife, Michelle McCool knows that he's "out so late".
AJ Styles spoke about this again during the match after The Undertaker got a beating from him as he told Undertaker that "Michelle should have never let you out". After throwing Styles off the platform, Undertaker mocked Styles and asked him if he was still going to talk about The Undertaker's wife and if he remembered her name.
A female WWE star said her life is in danger. Details HERE
Throughout this storyline, WWE have allowed Styles to use The Undertaker's wife's name in promos, and WWE reminded fans of that at WrestleMania 36 as well. By doing so, WWE have peeled off a different layer to the Undertaker character, and perhaps this is something they will do in future feuds involving The Undertaker as well.