The history of the Avengers in comics for the past ten years (and by extension, much of the Marvel Universe in general) has spun largely out of AVENGERS DISASSEMBLED and HOUSE OF M. The events from these two stories led into CIVIL WAR, which in turn spawned its own tributary subplots and developments.
The premise of DISASSEMBLED/HOUSE OF M was the Scarlet Witch losing control of herself and her magic going wild, mostly in attempts to resurrect her slain children. The catalyst of this storyline, however, was the encounter between the Avengers and the Justice League of the DC Universe in AVENGERS/JLA. It was that encounter with the powerful chaos magic of the DCU and the Gamemaster's revelation of the fate of her children that led to Wanda's subsequent breakdown.
It seems an interesting and ironic point that the past ten years of AVENGERS and Marvel Universe storylines might have their narrative root in the Avengers' encounter with the DC Universe.
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