Each War Hydra is driven into battle by two Beastmaster Apprentices who direct it with lashes and long-tined goads. The two Apprentices must remain within 1" of the War Hydra at all times. If the Apprentices are killed, the War Hydra must make a Monster Reaction test just like a ridden monster which loses its rider. A Beastmaster on foot may join the unit (replacing a lose Apprentice if you wish), but once the Hydra has taken a Monster Reaction test it always operates as an independent model. No other model may join a Hydra/Apprentice unit.

Any shooting against the unit gains the + 1 to hit modifier for a large target. If there are any Apprentices visible to the firing unit, roll a D6 for each hit. On a roll of 1 to 4, the Hydra is hit, on a roll of 5 or 6 an Apprentice is hit. If there is no Line of sight to the Apprentices then all hits are worked out on the Hydra (so it's a good idea to hide them behind it in your movement phases!)

In close combat, the War Hydra and any surviving Apprentices are arranged just like a skirmishing unit and models fight with opponents in base contact as normal. The Apprentices are adept at using the bulk of the Hydra to protect themselves, so that all enemies who can choose to attack them or the Hydra must allocate their attacks against the Hydra. The unit may only charge enemies which the War Hydra could normally charge (within a 90° arc to its front).