Id say they are prob gonna not see eye to eye completely but id say this new working closer will remain
Its cool to see where they go with it maybe the ynead followers will become 4th faction like harlequins
The lexicum describes khaines gate events like something trying to come through and is getting closer to doing so , after the 13th crusade its started to show hairline cracks!
Edit rumours it will finqly breach soon
http://natfka.blogspot.co.uk/2017/02/warning-fracture-of-biel-tan-spoilers.html?m=1
Edit 2: read play by play of the latest eldar stuff...yup the gate is opened by vect to kill his enemies but even he doesnt forsee the shitstorm that comes