‘Arrow,’ ‘Flash,’ ‘Supergirl’ and ‘Legends’ Crossover Has ‘One Unifying Threat’
It’d take a pretty big crisis to gather the likes of Arrow, The Flash, Legends of Tomorrow and Supergirl (from another universe), leaving The CW to assemble a pretty major threat. And while the big four-way crossover remains well under wraps, it seems one major threat will unite the four, rather than different big bads for each installment.