It was always going to get DLC, this was more or less cemented. But WHEN it was going to happen was an issue everyone had on their minds. Remember ER started and was still under development by FROM and Mizushima when the Covid-19 pandemic started which altered somethings so badly and upended a lot of work schedules, quotas, etc... That's why also ER felt like it was still "missing" things and having those three gigantic arenas/coliseums in Limgrave, Caelid, and Lyndell which players couldn't access but clearly served some kind of purpose and point. But yes it was a matter of time: - Dark Souls released in September 2011; Artorias of the Abyss DLC didn't come out until October 2012 (13 months basically) - Dark Souls 2 released in March 2014; Crown of the Sunken King came out in July 2014, Crown of the Old Iron King came out in August 2014, and Crown of the Ivory King in September 2014 (4 months for DLC 1, 5 months for DLC 2, 6 months for DLC 3) - Bloodborne released in March...
