Since the publication of the Officio Assassinorum ebook there has been particular interest in one available unit - the Culexus assassin. Either as an opponent or as an ally Tau players should expect to see more Culexus assassins on the table than under the old Grey Knights codex version and as it is such an unusual unit I think it is worth it having a mini-tactica in its own right.
The key attraction of the Culexus assassin to a commander is their extensive set of special rules against psykers of all kinds. The Culexus is the single strongest counter in the game to army lists which depend on psyker powers and is extremely powerful against any army containing psykers. Against non-psyker armies the Culexus assassin will be less powerful but still carries some threat.
Adding a Culexus to a force
Each of the assassins may be taken as a single model detachment from the Officio Assassinorum and allies as a part of the Imperial Forces. A Culexus assassin is a handful of points less than a Razorshark fighter.
Special rules for assassins mean that they must operate alone - further special rules for the Culexus mean that it cannot benefit from psyker support. A Culexus in a battle brothers alliance may benefit from using transports but is generally little affected by the alliance level with the rest of the army.
A Culexus is a desperate ally for Tau, as this unit is designed and intended to operate alone this will rarely be a significant problem for a Tau force with such an ally.
Basic profile and general combat abilities
All assassins have strength and toughness similar to space marines with a 4+ invulnerable save. They have WS and BS of 8 and an initiative of 7. The Culexus has a unique defense in addition to its invulnerable save so that all attacks against it are reduced to WS or BS 1 - these are not snap shots so the assassin remains vulnerable to template and blast weapons. The Culexus has a leadership of 10 and is fearless.
The Culexus has 4 basic attacks which ignore armour and inflict instant death on a damage roll of 6. With high initiative and skill the Culexus is a dangerous opponent in close combat for most infantry but highly unpredictable against monstrous creatures such as Riptides who will be either unharmed or killed instantly. Invulnerable saves are the only form of defense against a Culexus' close combat attacks.
Although the Culexus lacks any conventional shooting weapon it has a shooting attack in the psychic phase with a variable number of shots with a range and power equal to a pulse carbine and an AP of 1. It may take as many shots as there are psyker levels within 12" plus up to 3 additional shots from the psychic dice pool. As a Tau force has no other use for the dice in its pool a Culexus would normally have as many as are rolled on a single die up to the limit of 3 when facing non-psyker opposition.
Tau commanders should be wary of the relative positioning when an opponent has both psykers and a Culexus. An opponent with both can choose to use their own psykers to power the shooting attack by positioning them within 12" of each other. With its high BS and low AP this can be an efficient way to turn warp dice into damage. As written the rules allow multiple Culexus to benefit from each psyker so where detachment limits are not applied very high outputs of high quality shooting are possible.
All attacks from an assassin have a -2 penalty to any look out sir rolls and the assassin can earn an additional VP should it kill an enemy warlord.
The Culexus assassin moves as a normal infantry model and may infiltrate and move through cover. An advantage of its shooting attack being in the psychic phase is that it may freely run in the shooting phase. Using this the assassin can perform a shorter range version of the JSJ familiar to Tau players and being a single small model is very good at using cover to avoid retribution from enemies that survive its shooting attack.
In a battle with no psykers on the table the Culexus assassin is useful but not especially powerful. It has respectable shooting and close combat ability but is vulnerable to massed fire which will kill it by sheer number of shots or to multiple blast/template weapon attacks. A single IA blast or similar can instant-kill a Culexus which fails its invulnerable save.
Use against psykers
The rule which has attracted so much attention to the Culexus is one which gives it a 12" radius anti-psyker null zone. Within this zone no blessing or malediction works and when a Culexus moves within range all such powers cease immediately. Additionally all warp dice generated within the zone go to the Culexus to feed its shooting attack and any attempt to harness warp power in the zone succeeds only on a roll of 6. Finally all psykers in this zone take -3 to their leadership.
The damage output of the Culexus is also considerably greater against psyker enemies. The number of shots for their shooting is increased by their presence as explained above, their BS against any unit with a psyker in increases to 10 although this rarely makes much difference. Additionally all close combat wounds inflicted against psykers inflict instant death. When targetting a unit containing a psyker the Culexus can use its one true shooting attack, the psyk-out grenade which will force the psyker to roll for perils - combined with the -3 to leadership this can be dangerous for the psyker. The range of the grenade is of course limited but with BS10 it generally hits the target and can be a useful way to soften up a target before assault. The Culexus itself is immune to psyker powers of all kinds.
The key value of the Culexus is its null zone which shuts down psychic death-star type units completely. With all blessings gone they are generally vulnerable to attack and can only escape the zone by conventional movement. Offensive powers are near useless when generated within the null zone, even if warp dice are available from beyond the null zone. This effect is the main reason why Culexus assassins will be seen on the table and it has the same value for a Tau commander as for any other. There is no comparable counter in the game to psyker death-star units which can and have dominated games, any army needing a counter to these powerful lists should seriously consider the option of a Culexus assassin.
As Culexus assassins become more commonplace the prevalence of psyker dependent armies will presumably drop until some new balance of between them is found, as between predator and prey.
Use with psykers
Until very recently the Culexus assassin was part of the Grey Knight codex and many Grey Knight players will have one in their collection. Although any psyker army must fear this assassin it is also powerful in their hands if they use it carefully.
A psyker army can use the warp charge from units out of effective range of their powers to charge up the shooting attack of the Culexus to considerable effect. When facing a psyker army such as the Grey Knights which contains a Culexus a Tau player should be aware of the considerable high quality shooting power that can be generated. A Culexus backed up by two combat squadded units of Purifiers can make 11 shooting attacks in a turn, a considerable threat to most units. The psykers providing the warp charge will suffer disadvantages as noted above but some, especially fearless units such as Purifiers, will take little practical penalty from this.
Defending against a Culexus
A Tau army is one of the forces least affected by a Culexus and should have no particular difficulty dealing with one. Massed fire from pulse weapons (or similar) will usually be sufficient to deal with the threat and units with good cover saves - such as Stealth suits - have little to fear from its shooting attack which has no way to ignore cover saves. The shooting attacks of a Culexus are only really dangerous to Tau units when backed up by warp charge from a psyker heavy army, in this case the Tau player must use cover as best as possible and decide between eliminating the assassin or the psyker units powering its attacks. Twin linked low-BS shooting such as that from gun drones is a cost effective way to deal with the BS lowering defense that the Culexus partly relies upon. A Culexus is extremely dangerous to Tau infantry in close combat, which is something of a non-issue as almost everything is dangerous to Tau infantry in close combat.
The blanks who are trained to become Culexus are described as repulsive to normal sentients - it has to be said that many players find the figure for the Culexus to be too realistically repulsive for their taste. Some suggestions for alternative modelling ideas to incorporate a Culexus in a Tau army are:
Taking a dark eldar medusae as your base it is quite easy to convert it to something akin to a mind flayer, representing an alien race unit who literally feeds on psychic power, yet does not get along well with others making them and their tau allies distrust each other.
Or you can have post-firewarrior Kais, given that he is mentally broken beyond believe after being practically possessed by Khorne-he makes sense both as an anti-psyker beacon, someone with abnormal stats, and someone that nobody trusts or gets along with
Happy to receive any comments or suggestions to improve this.
Last edited by nic
on Dec 12 2014 04:16, edited 3 times in total.