Okay, here are my conversion notes for using Tyranids in Horus Heresy (long post follows):
The following are changes that should be made to the 6th-edition Codex: Tyranids (henceforth CT6) and White Dwarf, issues 40, 41 and 42 (November 2014, henceforth WD40, WD41 and WD42). Note that only changes have been listed, rather than the full rules.
Principles
1. What follows is based on CT6 and WD40, WD41, WD42 as closely as possible, with only minor changes. Movement scores are found in the WH40K 9th edition Codex: Tyranids. I won't post them here as it feels like it might be a copyright infringement of some sort.
2. Changes are made for ease of integration into HH, with the expectation that armies will be built using the Crusade Force organisation chart from the HH rulebook (henceforth HH); note that tyranid forces can only ally with themselves. In general, what follows is intended to produce interesting, rather than spam or power lists, that will still stand up to other armies in HH.
3. Unless otherwise indicated, Special Rules in CT6 use the versions listed in HH, pp. 230-249.
Tyranids Special Rules (CT6, pp. 38-39)
Army-Specific Reaction –
Emperor Save Us, There’s More of Them!If a tyranid Troops unit is entirely destroyed, the tyranid player may choose to place it in Reserves. It then re-enters play in the Movement phase of the following turn, using the rules for a Flanking Assault (HH, p. 311). The tyranid player may only use this Reaction once per game.
(Thank you very much to
chaosreigns for creating this rule.)
Instinctive Behaviour – Hunt – Burrow and Hide: Instead of Going to Ground, the unit is Pinned, but also gains Stealth (see below).
Synapse Creature: In addition to the rules listed, a Synapse creature does not suffer Instant Death from an attack where the attack’s Strength is double or more the target’s Toughness.
In addition, the tyranids often use tactics based around using immense numbers of essentially disposable creatures to overwhelm their opponents; thus in missions that award Victory Points for units destroyed, only tyranid Synapse units count.Tyranid Monstrous Creatures: Certain creatures in this list are Tyranid Monstrous Creatures. This confers the following benefits and rules:
• The creature is Monstrous
• It has the Fear (1), Hammer of Wrath (1), and Move through Cover rules
• It has the Smash rule from WH40K, 7th edition, p. 171
• If wounded by an attack with Instant Death or Murderous Strike, it takes D3 Wounds, instead of being killed outright.
Warlord Traits:
• Nature’s Bane: The terrain piece becomes Dangerous Terrain. In addition to the benefits listed, an army whose Warlord has this Trait may make an additional Reaction during their opponent’s Movement phase as long as the Warlord has not been removed as a casualty.
• Heightened Senses: In addition to the benefits listed, an army whose Warlord has this Trait may make an additional Reaction during their opponent’s Shooting phase as long as the Warlord has not been removed as a casualty.
• Synaptic Lynchpin: In addition to the benefits listed, an army whose Warlord has this Trait may make an additional Reaction during their opponent’s Assault phase as long as the Warlord has not been removed as a casualty.
• Mind Eater: In addition to the benefits listed, an army whose Warlord has this Trait may make an additional Reaction during their opponent’s Assault phase as long as the Warlord has not been removed as a casualty.
• Digestive Denial: In addition to the benefits listed, an army whose Warlord has this Trait may make an additional Reaction during their opponent’s Shooting phase as long as the Warlord has not been removed as a casualty.
• Adaptive Biology: In addition to the benefits listed, an army whose Warlord has this Trait may make an additional Reaction during their opponent’s Assault phase as long as the Warlord has not been removed as a casualty.
Deep Strike Assaults and Flanking Assaults: Tyranid creatures are not restricted to a single Deep Strike Assault or Flanking Assault, as listed HH, pp. 310-11. Instead, each unit with the ability to perform these forms of arrival may do so on the turn that it becomes available from Reserves, as an alternative to arriving on the battlefield from the controlling player’s table edge. This means that a tyranid player may have several units arriving via Deep Strike or Flanking in different turns, depending on when they become available from Reserves.
Units
Hive Tyrants (CT6, p. 40):
Hive Tyrants are Tyranid Monstrous Creatures and Characters. They also receive a natural Invulnerable Save of 5+.
Indescribable Horror: The Hive Tyrant’s Fear rule is increased to Fear (2).
In an exception to the usual rules, a Hive Tyrant with the Wings Biomorph may join a unit of Gargoyles or Shrikes, following the usual rules for an Independent Character being a part of the unit.
Tyranid Warriors (CT6, p. 41):
Tyranid Shrikes count as having Jump Packs.
Tyranid Warriors and Tyranid Primes have the Line sub-type.
Tyranid Warriors, Shrikes and Primes have Bulky (3) instead of Very Bulky, regardless of whether or not they have Wings.
New Unit Type: Tyranid Warrior Support Squad:A Tyranid warrior unit of no more than three models may choose to equip each warrior with a Basic Bio-Cannon at the listed cost. The models do not have to all take the same weapon. However, the unit becomes a Heavy Support unit and loses the Line sub-type.
Gaunts: (CT6, p. 42):
Gargoyles count as having Jump Packs.
Termagants and Hormagaunts have the Line sub-type.
Hormagaunts have Fleet (2), and may re-roll a single D6 when rolling for Run or Charge moves. These replace the old version of Fleet and Bounding Leap.
Increase the WS of Hormagaunts to 4.
Genestealers (CT6, p. 43):
Genestealers and Broodlords have Fleet (3), instead of the old version of Fleet.
Broodlords have Bulky (2) instead of Very Bulky.
Genestealers and Broodlords may take the Shrouded (5+) special rule for a points cost of 3 points/model for Genestealers, and 10 points for the Broodlord.
Lictors (CT6, p. 44):Lictors have Bulky (3) instead of Very Bulky; Fear (1) instead of Fear; and Fleet (3), instead of the old version of Fleet.
Lictors have Shrouded (5+) instead of Stealth.
Zoanthropes (CT6, p. 45; WD42, p. 23):Zoanthropes and Neurothropes have Bulky (3) instead of Very Bulky.
Zoanthrope Broods also have the Brotherhood of Psykers rule from WH40K, 7th edition, p. 159. Wounds from Perils of the Warp must be randomly allocated within the unit, but ignore the reference to losing powers.
Maleceptors (WD40, p. 23)Maleceptors are Tyranid Monstrous Creatures.
Increase the WS of Maleceptors to 4.
Tyranid Guards (CT6, p. 46):Tyrant Guards and Hive Guards have Bulky (3) instead of Very Bulky.
Blind Rampage: The Tyrant Guard have Furious Charge (1), instead of the old version of Furious Charge.
Shieldwall: Ignore the reference to Look Out, Sir rolls. Damage allocated to units comprised of a Hive Tyrant and Tyrant Guards is always allocated to the Tyrant Guards first.
Venomthropes (CT6, p. 47):
Venomthropes have Bulky (3) instead of Very Bulky.
A Venomthrope’s Spore Cloud confers the Shrouded (5+) special rule.
Free-Floating Agents: Venomthropes only need to remain within 4 inches of each other to maintain unit coherency.
Toxicrenes (WD40, p. 21)Toxicrenes are Tyranid Monstrous Creatures.
Increase the WS of Toxicrenes to 4.
Tervigons (CT6, p. 48):Tervigons are Tyranid Monstrous Creatures.
Increase the WS of Tervigons to 4.
Raveners and the Red Terror (CT6, p. 49):
Raveners and the Red Terror count as Cavalry, instead of Beasts. They have Bulky (3) instead of Very Bulky.
The Red Terror’s Swallow Whole attack can be used against Infantry models, even if they have Jump Packs or Jet Packs. Models with any level of Bulky may not be swallowed.
Tyranid Artillery Organisms (CT6, p. 50):Biovores have Bulky (3) instead of Very Bulky.
Exocrines are Tyranid Monstrous Creatures.
Increase the WS of Exocrines to 4.
Tyranid Feeder Organisms (CT6, p. 51):
Haruspexes are Tyranid Monstrous Creatures.
Increase the WS of Haruspexes to 4.
Pyrovores have Bulky (3) instead of Very Bulky.
Carnifexes (CT6, p. 52):
Carnifexes are Tyranid Monstrous Creatures.
Living Battering Ram: Carnifexes have Hammer of Wrath (D3), rather than Hammer of Wrath (1)
Increase the WS of Carnifexes to 4.
Ripper Organisms (CT6, p. 53):
Ripper Swarms and Sky-Slasher Swarms have Move through Cover and Swarm, instead of the old Swarms rule.
Sky-Slasher Swarms count as having Jump Packs.
Mawlocs (CT6, p. 54):Mawlocs are Tyranid Monstrous Creatures.
Increase the WS of Mawlocs to 4.
Terror from the Deep: Ignore the reference to the Deep Strike Mishap table. If, once all casualties have been removed from the Mawloc’s arrival, it would be placed on or within 1 inch of another model, battlefield edge or Impassible Terrain, deal with it according to the rules in HH, pp. 310-11.
Trygons (CT6, p. 55):
Trygons and Trygon Primes are Tyranid Monstrous Creatures.
Hive Crones (CT6, p. 56):
Hive Crones are Tyranid Monstrous Creatures.
Increase the WS of Hive Crones to 4.
Hive Crones follow the rules for Flying Monstrous Creatures in WH40K, 7th edition, pp. 68-69. This includes having the Jink and Vector Strike special rules (WH40K, 7th edition, pp. 167 and 174).
A Gliding Flying Monstrous Creature counts as having a Jump Pack.
Replace the references to “Tank Shock” with “Ramming”.
Harpies (CT6, p. 57):
Harpies are Tyranid Monstrous Creatures.
Increase the WS of Harpies to 4.
Harpies follow the rules for Flying Monstrous Creatures in WH40K, 7th edition, pp. 68-69. This includes having the Jink and Vector Strike special rules (WH40K, 7th edition, pp. 167 and 174).
A Gliding Flying Monstrous Creature counts as having a Jump Pack.
Replace the references to “Tank Shock” with “Ramming”.
Tyrannofexes (CT6, p. 58):
Tyrannofexes are Tyranid Monstrous Creatures.
Increase the WS of Tyrannofexes to 4.
The Swarmlord (CT6, p. 59):
The Swarmlord is a Tyranid Monstrous Creature.
Old One Eye (CT6, p. 60):
Old One Eye is a Tyranid Monstrous Creature.
Living Battering Ram: Carnifexes have Hammer of Wrath (D3), rather than Hammer of Wrath (1)
Increase the WS of Old One Eye to 4.
Deathleaper (CT6, p. 61):
Deathleaper has Bulky (3) instead of Very Bulky; Fear (1) instead of Fear; and Fleet (3), instead of the old version of Fleet.
Deathleaper has Shrouded (5+) instead of Stealth.
Tyrannocyte (WD41, p. 17):Tyrannocytes are Tyranid Monstrous Creatures.
Mucolid Spore Cluster (WD41, p. 18):No changes needed.
Sporocyst (WD41, p. 19):
Sporocysts are Tyranid Monstrous Creatures.
Weapons and Biomorphs (CT6, pp. 63-67)
Melee Weapons:
Crushing Claws have the Armourbane (Melee) special rule.
Rending Claws have the Rending (6+) special rule.
Ranged Weapons:
Thorax Biomorphs – Shreddershard Beetles: These have the Rending (6+) and Shred special rules.
Biomorph Upgrades:
Adrenal Glands grant the Fleet (3) and Furious Charge (1) special rules.
Wings: Monstrous creatures with this biomorph follow the rules for Flying Monstrous Creatures in WH40K, 7th edition, pp. 68-69. This includes having the Jink and Vector Strike special rules (WH40K, 7th edition, pp. 167 and 174). A Gliding Flying Monstrous Creature counts as having a Jump Pack. Replace the references to “Tank Shock” with “Ramming”.
Tail Biomorphs – Thresher Scythe: Has the Rending (6+) special rule.
Bio-Artefacts of the Tyranids (CT6, p. 68)
No changes needed.
Powers of the Hive Mind (CT6, p. 69; WD42, p. 23)
Dominion: Is a Psychic Power cast during the Movement phase, and lasts until the start of the controlling player’s following Movement phase. When using this power, the controlling player may choose to have the Psyker take a Psychic check. If the check is passed, the range of this power is increased to 12 inches. If the check is failed, the power confers no benefit and the Psyker suffers Perils of the Warp.
Catalyst: Is a Psychic Power cast during the Movement phase, and lasts until the start of the controlling player’s following Movement phase. It confers Feel No Pain (5+) on the targets. When using this power, the controlling player may choose to have the Psyker take a Psychic check. If the check is passed, the targets receive Feel No Pain (3+). If the check is failed, the power confers no benefit and the Psyker suffers Perils of the Warp.
The Horror: Use the Telepathic Hallucinations Psychic Weapon from HH, p. 325. For the purposes of this power, the Psyker is considered to have a BS of 3.
Onslaught: Is a Psychic Power cast during the Shooting phase. When using this power, the controlling player may choose to have the Psyker take a Psychic check. If the check is passed, the controlling player may choose an additional friendly unit to apply this power to. If the check is failed, the power confers no benefit and the Psyker suffers Perils of the Warp.
Paroxysm: Is a Psychic Power cast during the Movement phase, and lasts until the start of the controlling player’s following Movement phase. When using this power, the controlling player may choose to have the Psyker take a Psychic check. If the check is passed, the controlling player may choose an additional target unit to apply this power to. If the check is failed, the power confers no benefit and the Psyker suffers Perils of the Warp.
Psychic Scream: Is a Psychic Power cast during the Shooting phase. When using this power, the controlling player may choose to have the Psyker take a Psychic check. If the check is passed, the roll for Wounds caused is increased to 3D6+3. If the check is failed, the power does no damage and the Psyker suffers Perils of the Warp.
Warp Blast: Is a Psychic Weapon cast during the Shooting phase. Follow the Psychic Focus rules given for the Psychic Weapons listed in HH, pp. 323-325.
Spirit Leech (Neurothropes): Is a Psychic Weapon cast during the Shooting phase. Follow the Psychic Focus rules given for the Psychic Weapons listed in HH, pp. 323-325. For each Wound inflicted by Spirit Leech, 1 additional shot may be made when the Zoanthrope Brood uses Warp Blast immediately afterwards. These additional shots may not be carried over into the next turn.
Psychic Overload (Maleceptors): Is a Psychic Weapon cast during the Shooting phase. Follow the Psychic Focus rules given for the Psychic Weapons listed in HH, pp. 323-325. Note that the Psychic Check must be taken for each of the up to 3 times that the Maleceptor may use this power, so each use increases the chance of Perils of the Warp.
Comments, suggestions, and insults welcomed.