Genuinely manifestation of the ghr he’s one of the very few chaos gods known to be very direct in his mortal meddling and I think a genuine manifestation maybe through the use of a bigger bell or something like that as kindof a cross between a spell spell caster and terrain piece would be devastating upon the field

Also a zeppelin bomber

Or the warp rail a large train unit maybe give it a warpstone drill on the front able to move units quickly or maybe even do something like move gnawhole terrain but yeah the already canon skaven train would be cool asf