So you've just joined for the first time as a Xenomorph? No idea what you are doing? This Space station 13 guide is pretty good as an introduction to the interface! Otherwise, let this guide get you up to scratch!

As a foreword, rounds on this server usually last between two to three hours! Make sure you have the time commitment to sit a full round.

The Rules

While it's not fair to shove the rules down your throat, Aliens: CM is a roleplay focused server and as such has an extensive list of Rules. It's highly recommended you spend some time reading the rules to ensure you don't accidently break any. Thank you.

Character Setup

For the most part this part is simple, you'll create your character on the setup character page. If you want to play Xenomorphs, check the box that says you're interested in alien roles. Otherwise, as an alien, it won't really matter what your character looks like. As part of an alien Hive, you'll be assigned a number. Welcome to the machine. Click the [Join the Hive!] button and you should be in, if there are no slots available in join the hive you'll have to observe and wait for a larva to grow inside of one of the infected mobs, if there are any.

Becoming a larva: When the alien embryo has grown a new larva is spawned inside the host and (You) the candidate player is given control over the larva if your xenomorph preference was on. You can then trigger the chestburst sequence by just moving. After about 20 seconds of not bursting the larva will automatically chestburst, whether it is controlled by a player yet or not. If a doctor removes the embryo after it has grown into a larva, the doctor extracts a live larva out of the human instead of a dead embryo.

Your First Game

For your first run, try and join a round before it starts. It's no big deal to join in the middle, but starting a round will ensure you aren't born into a difficult or deadly situation. The general interface including the alien one can be found here.

How to Communicate

Communication is very important! Use the box at the bottom of the screen. There are several methods, but just know three for now:

(1) Use the hivemind to talk to the whole Hive. Examples:

Say ":a I live!!!"
Say ":a There are multiple tallhosts in Medbay."
Say ":a We are under attack from the south!"

(2) Talk to any alien in your local area, aka with your field of vision. (You can not talk through walls. If you can't see the terrain they are on, they can't hear you. ) Examples:

Say "Please lay more eggs, your Highness."
Say "Follow me."
Say "What should I do?"

(3) Talk in local out of character (LOOC) to ask questions about the game and how to do things. You can toggle LOOC chat in the menus if it's distracting. Examples:

LOOC "How do I upgrade? How do I do X?"
LOOC "Why is there so much lag?"
LOOC "Did you see the touchdown in the Seahawks game?"

The Alien Life Cycle

Xenomorphs are essentially parasitic insects. A Hive has only one Queen. The Queen lays eggs. The eggs mature after several minutes. Mature eggs contain a larval facehugger. The facehugger stays in the egg until disturbed. Facehuggers can only be picked up by the Queen, drones, hivelords and carriers (click the mature egg with an empty hand, then click the facehugger) or the hugger will attempt to attach itself to any host that gets close. If you need to return a facehugger back inside of the egg, drop it on top of the egg and after 30 seconds it should crawl back inside. The facehugger infects a host by implanting a larva inside its host. Because larvae require time to mature, the Xenomorph Hive will guard infected hosts and secure them into nests to prevent escape. Once mature, the young adults burst out of the host. They are colloquially called chestbursters and Larva may be a misnomer. This kills the host. Chestbursters are extremely weak at first, but given time can evolve and mature into several much stronger forms.

Waking Up

You'll usually wake up as a chestburster or Larva. Yes, you're an evil-looking snake-lizard-thingy, but you're basically a baby. You're very weak and should avoid conflict. You want to slaughter, not get slaughtered. Your first priority is to evolve into something bigger. So get out of danger and stay alive. If you wake up inside the Hive, stay there! If you wake up outside the Hive, there's a circular indicator on the right side of your screen that always points at the Queen. She's probably at the Hive, so go there. If she's outside the Hive, you may want to ask where she wants you to go. If you join late in a round, you may wake up in strange places. Remember that your first priority is to stay safe and evolve into something bigger. Please don't go awesoming around the map by yourself.

Click the [STATUS] button on the right side of your display. As a larva, you can evolve when both your indicators are at 100%. Xenos cannot evolve without an active Queen. Stay safe until these indicators reach the top. When they do, click the [ALIEN] button on the right part of your screen and click evolve . Many players ask the Queen what they should evolve into, but you'll have the final decision of Drone, Sentinel, or Runner. Check the next section for details.

Who Orders Who

Take a look at the Alien Evolution Chart. There are four tiers of aliens. Not every player can evolve to the top, because there are only so many spots available at each tier. The Queen is at the top. She runs the Hive. The third tier (frequently called T3) are the Carrier, Hivelord, Ravager, Crusher, Boiler, and Praetorian. These are comparable to Marine officers. Look to them for leadership. The second tier (frequently called T2) are the Hunter and Spitter. These are advanced versions of the bottom tier aliens. The Drones, Runners, and Sentinels are the first tier and make up the meat and potatoes of the Hive. If it's your first game, avoid evolving past the first tier unless it's necessary for the Hive. Allow more experienced players to take these more complicated roles.

Drones are very important supporting players, but not in combat roles. It makes an excellent choice for your first game. Drones have two primary functions. The first is building walls, doors, nests, and resin to create and protect the Hive. The second is planting as many weeds as possible to expand the Hive. You can't go too wrong if you're planting weeds! All aliens are more robust on weeds. Read more about Hives.

Sentinels are the primary defenders of the Hive. This includes defending the Queen. The other primary duty is making sure that no captured hosts escape to wreck the Hive. The ability to spit neurotoxin really helps. Unless the Queen says so, you should remain inside or around the Hive at all times. If live hosts are nested, you should remain close by to stop them from escaping. At the beginning of the round, you should be guarding the Hive and shepherding any hosts.

Runners are the Hive's scouts. You're very weak at first, so don't rush out at any enemies. It's easy to tell inexperienced Runners because they tend to die quickly. Don't let that happen to you. Think of yourself as a ninja. Speed and cunning are your weapons, not brute strength. Your primary role is to scout around the Hive, identify any threats or possible hosts, and report back to the Hive. Stay in the dark. Communicate lots. At the beginning of the round, Runners are expected to quickly bring back hosts like monkeys, etc., to the Hive to be infected.

You should obey any orders given to you by your Queen. It is a hive mind and you have no free will. The only exception is if you are given orders that violate the rules. (Should you be given orders that would violate the rules then you should contact the admins by ahelping.) If an alien that outranks you asks for something, try to do it. Assisting experienced players is a great way to learn the game.

Upgrading

Check your [STATUS] button on the right hand side. You can either upgrade or evolve when both meters are at 100%. Keep an eye on your status and watch for messages hinting that you're ready to upgrade. When it's time, click upgrade and you'll advance in rank from "Young" to "Mature". Your strength and abilities get better every time you upgrade. Check your [STATUS] again and upgrade when you can. Because of upgrades, the Hive gets much stronger as time progresses. You're an investment for the Hive and it's strategically very important to stay alive. If you're new, please avoid the evolve button and let more experienced players play the more advanced Xenos. Crawl before you run.

Alien Abilities

There are others, but you should especially be aware of these. You can find them under the [ALIEN] tab on the right hand side: For All Aliens:

toggle darkvision - Arguably should have its own HUD button. Aliens can see in the dark. Marines don't. Use this frequently to check where the Marines can't see. It's hard to shoot something you can't see or find. It's also hard to defend against something attacking out of the darkness.
check hive status - Provides a count and list of all aliens. Check the strength of the Hive and know which direction to evolve.

Drone

secrete resin - Calls a sub-menu for building walls, doors, membranes, nests, and sticky resin.
plant weeds - Plants weeds.
secrete pheromones - Calls a sub-menu for helping nearby aliens. Frenzy is offensive, Guard is defensive, and Recovery is healing.

Sentinel

spit neurotoxin - Missile weapon that stuns hosts.
corrosive acid - Calls a sub-menu to melt nearby items. Xenomorphs hate metal. Melt everything useful to the Marines.

Runner

pounce - Quick jumps several squares. Can be used with the middle mouse button or with a sub-menu. Offensively, can tackle and stun Marines. Defensively, can quickly dodge metal spitters. It takes time to recharge after use.
hide - Your character is normally drawn in front of any graphics like tables or boxes. When you hide, your character will be behind those graphics. Bigger things are better. Marines may not notice you. Use this ability offensively or defensively. Toggle it off if attacked, because you may be more susceptible to attacks once you're discovered.
toggle darkvision - So important for Runners, it's listed again. Stay in the dark until you're ready.

Combat

At the beginning of a game, the Hive is desperate for hosts to infect. The Queen will issue a standing order forbidding the slashing of hosts. While this order is in place, all aliens will do significantly less damage in combat. You might want to avoid conflict, but you can still tackle and hold hosts with your Disarm/Grab intents to try and move them to the Hive. At some point, the Queen will allow the slashing of hosts and your combat power will improve significantly. Check this order with the [STATUS] button.

First tier Xenomorphs have four primary methods of damaging Marines:

Claws - With Harm intent active, click on a host when you're adjacent or sharing a spot.
Facehuggers - Note this is only for Drones (and Queen): Hold a facehugger with your active hand. With Harm intent active, click on a host when you're adjacent or sharing a spot. The hugger should attach. You have two hands and can use two facehuggers if you click quickly.
Tail - Xenomorphs have a powerful tail. Ready it by clicking the button at the bottom of the screen or using the ready tail attack button on the right side under [ALIEN] special powers. When you use your claws, you'll also use your tail, but not on objects like windows and sentries. Readying this attack drains plasma.
Spitting - Sentinels can spit neurotoxin to stun hosts from afar, and the more evolved Spitters can spit burning acid.
Pounce - Runners can pounce onto unsuspecting marines to slash and weaken them.

You can torture Marines in different ways by targeting different parts of their bodies? Try and see! Be entertained by the screams while you experiment!

How To Infect Hosts

One of the Hive's most important duties is reproduction. The Alien life cycle is complicated.

Eggs

The Queen should lay as many eggs as possible. Eggs have several functions. First, egg fields are basically minefields. If hosts run near eggs without clearing them out, they'll get hugged and infected. The Queen should lay eggs in important defensive positions. Second, eggs provide ammunition for the Hive. Drone caste Aliens, especially Carriers, will grab facehuggers and fling them at hosts. More eggs means more ammo. Third, eggs are necessary for infecting captured hosts. Note that you can place facehuggers back into their egg by dropping them on the same tile as the egg, and after 30 seconds the hugger will crawl back inside the egg. The facehuggers will die outside of their eggs if they can't crawl back in one.

Using Facehuggers

Note this is only applicable if you are a Drone, Hivelord, carrier or the queen: Hosts can get hugged actively or passively. Hosts walking through mature egg fields will get attacked by facehuggers and infected. Or, aliens can fling facehuggers at hosts to actively cause an infection. Some helmets can stop one or more facehugger attacks, so be careful when attacking some marines. Once attached, a facehugger will stun its host. Once a host is infected, the aliens will become aware of any baby sister inside through an icon. The icon gets bigger as it matures.

Moving Hosts

Remember that at the start of a round on Lv 624 specifically, there is a fog wall blocking the river so you'll have to use tunnels to bypass this. A host can be dragged to a new location by ctrl-clicking on the host. Certain aliens can also devour a host (click the host with grab intent active and then click yourself) and regurgitate it (use the regurgitate button in the [ALIEN] tab) after carrying it to a nest. Carrying it inside is faster. A devoured host will die at some point between 15 and 30 seconds inside an alien, so be careful holding them too long.

Securing Hosts

It may not be necessary to secure small hosts (like monkeys) into a nest. These hosts are not dangerous and the young chestburster may still grow and develop. Still, a clean Hive is a happy Hive.

Dangerous hosts (like Marines) should be secured into a nest. Otherwise, they'll run or shoot up the Hive. This is very bad. A Drone, Hivelord, or Queen should set up nests for dangerous hosts using the secrete resin function. These nests should be in a secure location, away from the center of the Hive, and away from any young chestbursters. Move the host to the nest. Then click the host and drag it onto the nest.

Injured hosts are less dangerous. But injure them too much and they'll die before their time. Should hosts be injured just enough to make it impossible for them to escape? Maybe rip off their hands or feet? (A bleeding host, is generally a dead host. )

Guarding Hosts

At least one Sentinel, Spitter, or Praetorian should guard these hosts until their usefulness ends. The spit neurotoxin function is made for this because it stuns the host until they can be placed back in a nest and secured. Hosts can also be tackled by clicking on them with Disarm intent. This stuns the host.

The area surrounding these nests should be constructed to provide maximum safety. A checkerboard pattern is regularly used. See Drone Tactics. Place a single door, and put four nests adjacent to it. (Above, Below, Left, & Right). Then surround those nests with doors. This allows Sentinel castes to guard all four nests by standing in that initial door. There are other effective methods, including building nests next to solid walls or walling off small rooms full of nests with only one exit.

After Birth

Listen to the screams and celebrate the birth! Prepare the nest for another host. Move any unconscious chestbursters to a nursery. This should be located in the most secure part of the Hive.

Tips

Plant Weeds often to spread weeds as far as possible. Plasma is the life force of the xenomorph.
Aliens only heal when standing on weeds, and you will die if they've been knocked into critical and aren't on weeds.
If you are injured, you will regenerate plasma at a much slower rate.
Live to fight again. Fall back to weeds when wounded. Heal up before re-joining a battle.
You can regenerate plasma while injured, and health, off weeds if you are affected by recovery pheromones. Don't try this if you are critical.
Aliens do not need to breathe. You can traverse open (and oxygenated) space without permanent damage.
As a Queen, there is no greater advantage you can give your brood than to plant as many eggs as possible. Not only is it an excellent defence, but a powerful weapon when your sisters have access to facehuggers to immobilize their prey.
Aliens are in a hivemind, you have NO free will.
When you are on fire, get on weed and click RESIST to roll on floor until extinguish. Disarm others (shove) do NOT help extinguishing fire, just drag them on weed.
Purple Sac itself without weed on floor still count as a weed so aliens can heal on them.

Xeno Roleplaying Guide and Expectations

You are an extension of the will of the Queen. If there is a Queen, her will MUST be followed. No exceptions. If she orders you to run to your death, start running.
Remember that Queen's word is law unless it breaks a rule in which case you should ahelp it.
You are a hive-mind, information is shared - Because a hive-mind works on the INSTANT transmission of information between all those connected, you CAN use words like "shuttle" or "hydro" to describe things. It's assumed that because you are a hive-mind, if you say "shuttle" your alien character is actually understanding what your are describing instantly (because, it shares a consciousness with you), but since we can't actually "emulate" this, using English to describe things is OK.
Killing a nested+infected host at ANY TIME is a bannable offense, and don't un-nest just to kill. It's counter-productive to your cause of growing the hive. If a marine escapes the nest and uses a weapon to resist, THEN you may kill them, but you should try to tackle and renest them. Remember: The more hosts you get and keep alive, the bigger your team. EXCEPTION: The queen MAY kill any marine she wants at any time, provided she has an RP justification (if asked by the admins). This power does NOT extend to aliens following the Queen's orders.
You do not know that Marines are coming to the planet. Furthermore you cannot prepare defences on or around the dropship landing zones prior to the Marines arrival.
When you die, you are a 100% NEW XENO. However, your previous life is part of the hive-mind, so you CAN use/pass on knowledge your previous "life" knew, as the hive "should" know it. (i.e. Dying to a mine near the Nexus means you can say "There are mines by the nexus, lookout", but you can't say "I WAS THE PREVIOUS QUEEN, I CLAIM QUEEN, OBEY MEH".
Roleplaying Guidelines

Additional Reading

The following are some good guides and examinations that go further into explaining other details of the game:

Xeno Roleplay Discussion

Roleplaying Guidelines

Ultimate Xeno Write-Up

How to be a respected Sister of the Hive

Xeno Strategy Guide

My Badass Hive Guide

The Value of Darkness

TFW Playing Xeno after a few days