At one time it would have been several different guys in the TNA/Impact years. Once it could have been AJ Styles. But Dixie hurt that with her situation where she was forced to cut contracts and tried doing that with AJ. Then you had Abyss who had been there since nearly 2002 but his body finally was giving out almost like Undertaker's had. Abyss its sad because the hardcore style really took a bad toll on him and by 2018 he retired and left to work in WWE. James Storm has been sadly booked up/down for years and could be that. But its like he rarely shows up in Impact anymore at times.
Its likely gonna be Sami Callihan now. As he told in a promo , he is the heart and soul of this place. So he's crazy and pure psycho but seems to love Impact.