The most simplest way to describe this really weird storyline and everlasting effects, is that DC decided to do a massive revamp. DC was in desperate need of a revamp, especially seeing has how its major characters had (at the time) around 50 years of history and had never aged or changed a bit, especially Superman (I hate that big chested git and especially pre-crisis Clark Kent). Plus it needed to eliminate to countless amounts of alternate universes that had plagued the DC since about the 1960's when they decided to re-activate the Justice Society of America on Earth-2. Also it needed to reestablish the Golden Age heros into the proper time and also include heros that DC had taken over, mainly Captain Marvel and the Marvel Family (you know the ones that say Shazam alot).

The 12 issue maxi-series, sent all the heroes against some being called the Anti-Monitor, which has been destroying all the alternate earths on its goal to destroy the entire multiverse. Many heroes died defending the multiverse, most notably Barry Allen (Flash) and the kryptonian Supergirl, has well has others (Note out of the many that died, most where killed to be either revamped or the be gotten rid of away from the time line. The Flash was mainly killed off because his sales where down and they wanted new blood).

The heroes succeeded and where able to stop the destruction of some of the earths, mainly Earth-1(Silver-Age heroes), Earth-2(Golden-Age heroes), the Earth containing Captain Marvel, and Earth Prime(us!!!). Afterwards, most of the earths got amalgamated into the one we know today, and no Earth Prime didn't get included in the deal.

Alot of changes occured, mainly in the Superman, Batman and Wonder Woman continuity. The past 50 years history was erased and the heroes had now only been around for about 8-10 years (fitting in with Silver-Age characters). Superman himself got powered down and know lives more like a human when he is Clark Kent, plus all other Kyptonians where killed off (like Supergirl (who got brought back has a shape shifting being), Comet and the Super-pets, the Fortress of Solitude, and Kandor the city in a bottle), but most have been brought back in some form or another (Comet is now a chick that shapeshifts into a guy? see current Supergirl series or just pick up Supergirl 25). Batman is alot darker and all the campyness has been destroyed (does anyone remember the Rainbow and Bullseye Batsuits? or perhaps the Anti-shark Bat Spray (which somebody has in fact developed!!!!!!!)). Wonder Woman was given powers!!, previously she had to rely on her Amazonian training and her bracelets, and a better origin.

Jade didn't really change that much, but I would like to know how come she's in about her mid 20s and her real parents are Golden Age characters (in other words they are probobly 70ish today, then again how she was about the same age has them pre-crisis).