To represent the unique nature of the Tyranid bio-ships many of the standard Battlefleet rules are modified as detailed below. The rules are laid out in accordance with the turn sequence. Any rules not specifically modified apply as normal to Tyranid ships.

All Tyranid vessels use Instinctual behaviour unless the Hive Mind (ie you!) tells a ship or squadron to do something different via the psychic influence of the hive ships. For ships or squadrons using instinctive behaviour read down the list of conditions cited on the table below and and give them the first appropriate action or special order you come to. No command check is needed for special orders, but there may be specific activities that must be undertaken in the vessel's movement.

For example: A Tyranid cruiser wishes to move towards the enemy fleet in support of its Hive Ship but fails the Ld test. We check the Instinctive Orders table - there are no celestial phenomena or enemy ships close or in range but there is a planet on the table. The Cruiser has to move towards the planet even though this actually takes it further away from the enemy fleet it wished to close with.

Only Hive ships have a Ld value, which is purchased at a fixed value on the hivefleet list. During the Movement phase each Hive ship can make a Command check to change or ignore instinctual behaviour for themselves or another ship/squadron within 45cm. If the test is successful the Tyranid player has control of the ship/squadrons' movement and may place it on special orders if desired. Ships/squadrons placed on reload ordnance special orders must still roll a D6 to complete them as specified by the instinctual behaviour chart below. Rolling doubles for reload ordnance special orders does not cause Tyranid ships to run out of Ordnance

Attempts to use synaptic control count as a command check so a Hive ship can keep testing until a command check is failed.

However, if one hive ship fails a command check this does not prevent another hive ship attempting to use synaptic control. In effect each hive ship can make at least one attempt to override instinctual behaviour.

For example: A Tyranid Drone wishes to overcome its instinctive orders so tests on the Ld of a Hive Ship within 45cm but fails. Because there is another Hive Ship within 45cm it may test again and may continue to do so so long as there are Hive ships within 45cm of it.

During either players turn Tyranid ships/squadrons can go onto Brace for Impact orders by testing against the Ld of the nearest Hive ship. As normal this order is only removed at the end of the Tyranids' next turn. Ships on Brace For Impact orders which are acting instinctively obey the movement restrictions listed above but do not change their special orders.

Tyranid ships always target the nearest enemy ship unless a special scout-drone 'highlights' another enemy within range. No Ld test is allowed for Tyranid ships to select a target other than the nearest. Ordnance markers are always ignored and may not be fired at. Scout-drones highlight all enemies (including ordnance) within 15cm, and these can be targeted freely by any other vessels in the Tyranid fleet which are within range.

Bio-plasma: Bio-plasma is treated like a lance shot - roll 1 dice per point of strength, and it hits on a 4+ regardless of armour.

Because it is a relatively slow moving attack, like that of a bomber squadron, bio-plasma ignores shields. Unfortunately, this factor also limits the range of bio plasma to 15cm.

Pyro-acidic batteries: These Tyranid weapons work by launching compact organic shells containing virulent toxins and pyroacids. These can cause considerable damage on impact, but it is the release of their ravening payloads into the confines of a ship that can prove the most deadly. Pyro-acidic battery fire is worked out in the same way as an ordinary ships weapon battery. Any ship which is hit by Pyroacid weapons has a chance that they will continue to be eaten away by the deadly bioagents. Ships which suffer a critical hit from a pyro-acid weapon automatically receive an additional fire critical as well (it's not actually a fire, but the long-term effect is comparable).

Feeder Tentacles: Many Tyranid ships have huge tentacles which they use to 'feed' on planetary atmospheres, and which can also be used to punch through the hull of a ship allowing the Tyranid organisms inside to assault the enemy. When the ship moves into contact with an enemy ship, it attacks with its feeder tentacles. Roll a D6. On a score of 1, 2 or 3 it makes this many hit-and-run attacks on the target as scattered broods of Tyranid creatures rampage through the vessel. On a score of 4+, enough bio-engineered nasties are delivered to initiate a full-scale boarding action which is resolved in the End Phase. In this case the Tyranid ship may still fire fire and does not suffer any damage from the boarding action.

For example: A Tyranid ship equipped with Feeder Tentacles is in contact with an Imperial ship, it rolls a D6 and scores a 4. In the End Phase the Tyranid player may roll for a boarding action but the Imperial player may not because Tyranid vessels are just too scary to board. In addition the Tyranid vessel may still fire its weapons in the shooting phase because this has no effect on the boarding action being commenced.

Massive claws: Tyranid vessels are terrifying in combat at close quarters. Not only are they packed full of bio-engineered killing machines, often the ships themselves have specially evolved claws designed to rip through the armour of its target, or crushing mandibles that latch onto the ship's prey and then slowly but inevitably tear through decks and gantries. When the Tyranid ship moves into base contact with an enemy, roll two D6, each roll of a 4+ inflicts one hit on the target, ignoring shields. If both attacks hit then the vessel has grabbed the target in its fearsome grip and will not let go until either it or its prey is destroyed.

Neither vessel can move if they are of the same class or smaller (ie capital ship to capital ship), a larger class vessel may still move but only at half rate. Both ships may shoot at half effectiveness (nova cannon and similar special weapons cannot fire). In every End phase roll to attack again (two dice needing 4+ to hit). If both attacks hit when a vessel is already grappled then it takes a third additional hit. Either ship may conduct boarding actions as normal. Massive claw attacks can cause critical hits as normal.

Tyranid ships do not have shields in the normal sense. Close range protection is achieved by the bio-ships discharging clouds composed of millions of mine-like spores. Spores are more accurately a form of ordnance, and are explained fully in the ordnance rules. However it is worth noting that while a bioship is protected by spores in base contact it counts as being shielded both for shooting and potential damage from celestial phenomena.

Tyranid ships do not have turrets. Interception of enemy Ordnance is undertaken by spores.

Some Tyranid ships may have launch bays or torpedo batteries. Tyranids may only launch boarding torpedoes and assault boats, or rather their biological equivalents in the form of giant hull-boring worms, ether-swimming brood carriers, protazoid enzymes, ravening limpet mines and the like.

Every Tyranid ship has spore cysts capable of launching spore clouds which are a special type of ordnance. Spores have a speed of 15cm, and act like fighters against other ordnance. They also count as blast markers for the purpose of shooting through them. If they are on a friendly ship's base then they act as a shield - each hit removes a spore and it is replaced by a blast marker. If a spore moves into contact with an enemy ship then it acts like a bomber. Spores may be launched in waves. Spore cysts must be reloaded before launching again like other Tyranid ordnance.

Spores are extremely simple organisms and even with the influence of the hive mind they only move according to a crude form of instinctive behaviour. This cannot be overcome by using hivemind influence.

Representing Spores: Use the card asteroid counters from Battlefleet Gothic to represent spore clouds. Don't worry about the fact that they are different sizes too much, the chances are that the Tyranid player will run out of big ones to put down long before it becomes an issue. I'm told that dried peppercorns look good as models spores if you want to try basing some up.

Tyranids are a horror in boarding actions. A fearless, animalistic rush of clawed, fanged monsters has been the death knell of many a ship. Tyranids always count double their boarding value, plus they roll two D6 and use the highest result in boarding actions.

The nightmarish innards of a bio-ship are an environment hostile enough to rival the worst death-worlds. Even finding a target amongst the organs, nerve centres and arteries is difficult, and in the face of a horde of enraged Tyranid bio-constructs it often becomes fatal. Because of this Hit and Run attacks against Tyranid ships roll two D6 and take the lowest result. Tyranid ships may initiate Hit and Run raids as detailed in the battlefleet Gothic rulebooks. The Tyranid player adds +1 to the result when making Hit and Run raids.

No crew would ever surrender their vessel to the Tyranids, or let themselves be consumed by the horrors one by one, trapped in their metal tombs. Many times desperate vessels have destroyed themselves rather than succumb to that fate. To represent this capital ships can attempt to self destruct when boarded by Tyranids by passing a leadership test in the End phase. If the leadership test is failed the crew must face their terrible fate at the hands of the Tyranids. If the test is passed roll a D6; on a 1- 3 the ship suffers catastrophic damage result of plasma drive overload. On a 4-6 the ship suffers the warpdrive implosion result instead.

Jervis Johnson

When answering your questions Pete noticed that there seems to be some confusion in how the ordnance phase works. Below Pete explains how the ordnance phase should be played. This applies to BFG in general and not just Tyranid players.

Reading some of the queries on the Tyranid Hive Fleet I came to the conclusion that there was a measure of confusion about the sequence of events within the ordnance phase that was worth clarifying.

Within each ordnance phase the phasing player moves his ordnance and then the non-phasing player moves his ordnance. The sequence in which the ordnance is removed is entirely up to the controlling player. This means that you could choose to move your fighters first to intercept enemy fighters prior to moving your torpedoes through the resultant gap.

This is particularly relevant for the Tyranids who move according to strict instinctive behaviour rules. You should assess instinctive behaviour conditions before you move each spore cloud or squadron of spore clouds. It is possible that early spore cloud movement could remove a condition before other spore clouds move. You cannot actually ignore an instinctive behaviour condition and sooner or later every spore cloud with a condition trigger must respond, unless something is done about the condition first.

As an example of this in the Imperial turn, a squadron of fighters is moved to within 30cm of a stationary Hiveship with 4 spore clouds on its base. When the Tyranid player moves his ordnance in the Imperial turn, all 4 spore clouds move 15cm toward the fighter. In the Tyranid turn the first spore cloud moves a further 15cm toward the fighter and both are removed. The remaining spore clouds return to the Hive Ship as it is within 30cm. The Hive Ship can then launch more spore clouds with no fear of them being immediately lured away.