A very handy method of transportation, but it is of a very expensive sort and somewhat vulnerable in combat despite its stack worth of hp.
Personally I prefer something like the
Sand Wurm 22/15/8/19/heavy, burrowing, footbiter, fire breath, ranged, mount
That's a devastating 30 attack (not counting leadership bonuses for a warlord riding shotgun) on ground units, which can come as a surprise attack from underground, and a respectable 15 on pesky air units.
Then there is the
Puppetmaster 16/4/6/19/heavy, simple croakamancy, simple dollamancy, leadership, dance fighting.
Might not look impressive, but it can build up an army of dolls to lead into combat, then replace fallen dolls with uncroaked as it goes, boosting them all up with dance fighting leadership. Oh, and don't forget access to new disciplines with every level. Shockamancy for when there is no army built up yet, foolamancy to make her harder to hit, dirtamancy for more varied units to control, flower power to poison her dolls, etc.