In my own fanfiction rainbow factory 4 (which is in Chinese), the rainbow is used as the ammunition for the elements of harmony, which is in turn the equestrian equivelent of nuke. Once the rainbow factory is destroyed, the equestria no longer hold the strategic deterrent, and the combined force of zebra and dragon invaded immediately before Equestria could rally an army. This is also the reason behind the ability setting for Rainbow Dash in the legends of the three kingdoms project. She can protect allies from damage, but every time she does so she risks dying.
再酷廿分 云宝黛西 9999
迷失 锁定技 当你的武将牌上有七张“虹”时，你须将它们弃置，失去“设备”，并把体力值调整为1
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