Board Thread:Warhammer 40k General Discussion/@comment-7186329-20130329201743/@comment-6078851-20130422030405

it's the necrons who'll have the final say on which stars would be destroyed. the celestial orrery, for those who don't know, is a necron device which shows a display of every single star in the galaxy. if someone 'switches off' a star on the display, the corresponding realspace star immediately goes supernova! luckily for everyone the celestial orrery is currently in the possession of a surprisingly considerate necron, but there is conflict among the necrons to gain possession of it.

that's why i mentioned 'if a pact could be struck with the necrons' then stars being used as weapons against tyranids could then be co-ordinated to minimize collateral damage (and with stars going supernova the collateral would be substantial even in the best case scenario).

if, however, the 'inconsiderate' necrons gain control of the C.O. then everyone is then in immediate, undefendable and terminal danger, except the tyranids as the bulk of their race isn't yet fully inside the galaxy.