For 10 points, name this massive crossover storyline that consolidated the Multiverse and has demarcated DC continuity ever since.
A battle in Markovia in this story's issue "Oblivion Upon Us" involves several of the main antagonist's Shadow Demons. Pariah and Harbinger were original characters of this story. In its issue "Death at the Dawn of Time," several heroes engage in a battle at the point when Krona created the multiverse. Several characters seclude themselves in a "paradise" dimension at the end of this story that includes an epilogue with the (*) Psycho Pirate in a mental asylum. One page in this story showed Flash destroying a cannon as his body gradually decays into nothing, and the cover to its issue #7 showed Superman cradling a dead Supergirl. George Perez drew this story, which involved countless heroes uniting to defeat the Anti-Monitor. For 10 points, name this massive crossover storyline that consolidated the Multiverse and has demarcated DC continuity ever since.
A battle in Markovia in this story's issue "Oblivion Upon Us" involves several of the main antagonist's Shadow Demons.
Crisis on Infinite Earths