Add the following rule, entitled Mounts:

Each Valkyrie may have exactly one mount. A Valkyrie without a mount shall not recruit Einherjar and shall not bid to do so.

Each Valkyrie’s mount is tracked in the GNDT. There are various mounts that a Valkyrie may chose to ride, and a Valkyrie’s choice of mount may affect his performance in other areas. All legal mounts are listed in this rule.

Horse: In the event that a Valkyrie riding a horse has a tied highest bid for an unrecruited Einherjar, the Valkyrie riding the horse always wins. If both Valkyries are riding horses, then the bid is resolved as if neither were.
Giant squirrel: As a weekly action, any Valkyrie riding a Squirrel may add five acorns to their total. This may not be done until seven days have elapsed from the Valkyrie’s adoption of the squirrel as a mount.
Dragon: Any Valkyrie riding a dragon at the time the Allfather announces a skirmish shall be considered to have 2 extra Moxie, 2 extra Combat and 2 extra Mysticism in that Skirmish. This does not affect the individual statistics of that Valkyrie’s Einherjar.
Giant Squid: Any Valkyrie riding a Giant Squid shall have their acorn bid doubled at no extra cost to themselves when bidding on an Einherjar whose Wikipedia entry strongly implies a connection with seafaring, the sea or ships. The Allfather is the final arbiter as to the validity of use in this matter.
Harpy: A Valkyrie riding a harpy when a Skirmish is posted may, after that Skirmish, pay an amount of acorns equal to x+1 to recruit the fallen Einherjar (where ‘x’ is the number of acorns paid by the Valkyrie who originally recruited it).
Vampire Bat: If a Valkyrie is riding a Vampire Bat, then all of his or her Einherjar become dishonourable. This effect does not expire if the Valkyrie changes to another mount.
Amner: Any Valkyrie riding Amner may only recruit or bid to recruit male Einherjar. If a Valkyrie already possesses female Einherjar when he or she switches to Amner, then those female Einherjar are ignored for the purposes of all rules until the Valkyrie changes their mount. If a Valkyrie riding Amner is involved in a Skirmish, all female Einherjar have their Combat reduced by 1 for the duration of that Skirmish.
Succubus: As a daily action, a Valkyrie riding a Succubus may pay x acorns, where x is the average amount of acorns spent on all recruited Einherjar in play, to recruit one of Loki’s Einherjar chosen at random by the Allfather.
Slepnir: Any Valkyrie riding Slepnir may undertake any daily action twice daily instead.
Fenrir: After every Skirmish, there is a 1% chance (DICE100 in the GNDT by the Allfather, with a result of 1 meaning success) that Fenrir will eat the sun. If he does so, all Dynastic rules are repealed, the Allfather becomes a normal Valkyrie and the game enters a period of meta-dynasty with no Emperor.

There may be no more than three of each mount in play at any given time, except Fenrir, of which there may only ever be one. A Valkyrie may change their mount to any other mount at any time, but not more than once every 72 hours, provided that it doesn’t cause there to be more than the permitted number of any mount in play.

Create a column in the GNDT entitled ‘Mount’.

How can we ride if we don’t have mounts?