Crossover
There was very little crossover between the various comics. Prior to the Civil War: Young Avengers/Runaways comic the Young Avengers and the Runaways had been mentioned in one another's comics.
The closest thing to a crossover centred on the fictional drug MGH. It appeared in numerous Marvel titles over the years previously and appeared in a two-part Young Avengers story in Autumn 2005. The following month, the Runaways were asked to fight the Pusher Man, an MGH dealer.
Gravity appeared in Marvel Team-Up, alongside other new heroes such as Araña and X-23, and Excelsior member Darkhawk.
In 2006, Marvel Comics published the crossover Civil War: Young Avengers/Runaways as part of the larger Civil War event.
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