Apologies, been a while, but here is v1.3 based on feedback.
Warmaster Allies & Mercenaries Trial Rules v1.3
COMBINATIONS
Alliances cannot be made between ‘good’ lists (Empire, High Elf, Dwarf, Bretonnia, Kislev, Witch Hunters, Wood Elf, Lizardmen) and ‘evil’ lists (Chaos, Skaven, Dark Elf, Vampire Count, Daemon, Beastmen, Chaos Dwarf). All other lists are ‘neutral’ and can combine with anyone.
WITHDRAWAL
Allied armies each have individual ‘break points’. If one army withdraws, the other(s) can continue fighting.
COMMAND
Allied armies each have their own general but orders given to allies incur a minus 1 command penalty.
MAGIC
Casting upon allied or mercenary units incurs a minus 1 penalty. Before dicing for any spell that affects multiple units, the player must declare whether they wish it to also affect their allies/mercenaries and apply the penalty if they do.
Dispel rolls against spells cast upon allies or mercenaries incur a minus 1 penalty. Also, when using a dispel scroll against a spell cast upon an allied or mercenary unit, roll a D6. On a 1 or 2 the scroll fails and cannot be re-used.
Allied armies can each take their own quota of magic items.
MERCENARIES
Armies may hire mercenary units from other lists. However, ‘good’ lists cannot hire from ‘evil’ lists and vice versa (see above). Anyone can hire from ‘neutral’ lists. Monsters, machines, and wizards/runesmiths (or equivalent) cannot be hired as mercenaries.
Mercenaries may be drawn from multiple lists but can never exceed one quarter of an army’s points. For cavalry, chariots, and artillery no more than one of any unit type may be hired from any list; for infantry the limit is two.
Mercenaries always incur a minus 1 command penalty. The exception is if mercenary heroes are hired; they order mercenaries from their ‘home’ list at no penalty and all other troops at minus 1. Mercenary heroes may bring their mounts.
If mercenaries blunder, do not use the normal blunder table. Instead roll a D6 and apply the following results to all mercenary units in the brigade:
1. Treacherous. The units transfer to the control of the opposing player from the start of their next command phase. If the mercenary hero rolled the blunder, they also change sides. These units do not count as casualties for the blundering player but recalculate each side’s ‘break point’.
2. Homesick. The units decide to go home. They are removed immediately from the table and count as casualties. If the mercenary hero rolled the blunder, they are also removed.
3. Mutinous. The units do not move. If they can shoot, at the start of the shooting phase they fire at the nearest friendly unit not in their brigade.
4. Disaffected. The units do not move and suffer a minus 1 command penalty for the rest of the game.
5. Craven. The units move a full pace away from the nearest enemy unit, even if that unit is not visible to them.
6. Greedy. The units move twice their normal distance towards the nearest visible enemy and charge if possible. If they engage in combat they do so with plus 1 attack per stand. If they win a combat round they must pursue, but will not advance because they will stop to loot the bodies.