The virtual "DC FanDome" from Warner Bros comes after real-world extravaganzas beloved by comic-book fans - such as Comic-Con - were canceled this year due to the coronavirus pandemic.
Headline billing went to The Batman, a dark, detective-style mystery take on the Caped Crusader which star Pattinson said had to shut down midway through production in March due to Covid-19.
Director Matt Reeves said his version - still due next year - is inspired by classic noirs like Chinatown and Taxi Driver, and will meet a "very human and very flawed" Bruce Wayne in his second year as Batman, trying to solve a series of crimes.
- DC (@DCComics) August 22, 2020
Like the rival, record-breaking Marvel films, several movies featuring DC characters including Superman are inter-connected, with shared storylines and crossover cameos.
Saturday's all-day event premiered footage and panels for follow-ups to blockbusters Wonder Woman, Suicide Squad and Shazam! - despite uncertainty over release dates, with many US theaters closed.
Johnson - the world's top-paid movie star who is now making his first foray into the superhero "universe" - teased next year's Black Adam, in which he will play a 5,000-year-old rebel slave determined to mete out ruthless justice.
"Things will never be the same. Because the hierarchy of power in the DC Universe is about to change," the former wrestler warned rival stars in typically bombastic style.
- ComicBook.com (@ComicBook) August 22, 2020
Footage of The Suicide Squad showed Margot Robbie and Viola Davis return alongside new cast members Idris Elba, John Cena and Peter Capaldi.
Kicking things off Saturday was Wonder Woman 1984 - penciled to be the next DC movie due out, in October, despite the pandemic.
"I really think the movie is so great on the big screen," said director Patty Jenkins. "We believe in putting it in the cinema... I can't wait for it to come out soon!"
The event comes as WarnerMedia - which owns the movie rights to DC comics - undergoes a massive restructuring, including the loss of hundreds of studio jobs.
Parent company AT&T is refocusing on new streaming service HBO Max, which has delighted comic-book obsessives with plans for a new director's cut of ensemble superhero movie Justice League.
Director Zack Snyder stepped down from the 2017 original due to family tragedy, and fans disappointed by the end product have spent years campaigning for his vision to be restored.
Saturday's panel on the "Snyder Cut" sent geeks around the world into social media meltdown, with Snyder confirming it will feature four, hour-long episodes - twice the length of the studio-cut original.
- DC (@DCComics) August 23, 2020