Originally designed as a melee class without attack power nor large HP pool, using Evasion instead of pdef, furtivity instead of cc, and the effects of the bonusses linked to the fast hits rather than the hits themselves, the Assassin saw, as time went by, an attack-speed 20% penalty on his dual wielding, a 50% damage penalty on his off-hand, his evasion capped against melee and made useless against magic/DOTs, his furtivity made hijackable by mobs, pets and players, and more recently the benefits of fast hits being removed. Assassin specializes in twin dirks or swords, and has a large range of offensive melee skills - but no nuke - and stealth skills to try and hide from their enemies. This class is a close ranged melee type who primarily uses evasion against mobs and hide/attack against players. If you enjoy ambushing lower players and being tactful then this is the class for you.
They are close combat evolution of the Striders. They do physical/melee damage and can disappear if needed via Cloak of Shadow.
Assassins are "pure damage dealers", and with actives and über-expensive weapon building, their damage output can be completely correct, yet it is not what makes the Assassin highly requested in Dungeon Parties.
Active skills for high Accuracy and Movement Speed.
Can disappear from sight for one minute with Cloak of Shadow (mobs, pets and some classes have skills which can uncloak a Sin- the Naga pet also has an active skill which can detect hidden assassins and thus attack them).
Assassins can use some abilities to control Aggro. This is achieved via Distortion of Rage, which not always works, as well as using Cloak of Shadow to remove aggro but not during a fight. (the mobs have to be close but not touching) This kind of aggro control is very useful in a boss fight or hard-mode dungeons to pull the enemy to the party, lose aggro and let the tank take it up and re-enter the fight to unleash some damage.
Evasion is part of the Assassin build as well, which allows the Assassin to increase their chances of avoiding incoming attacks. Caps near 70%, does not work against magic, does not work against DOTs.
With full DP buffs and Assassin Impact running, the Sins' damage per second is sometimes sufficient to unwittingly take aggro from the tank (despite the assassin using the Oblivion skill), which is an issue due to the lack of HP and self-heal.
Cloak: the most emblematic skill of the assassin. But once cloaked, you cannot use any weapon. And given that the skills will fail too because the sin has much less WIS than any other class, nobody fears anything from a cloaked sin.
Although Assassins are Damage Dealers, they only receive basic armor defense passives( sins only get lvl 15 defense mastery, when knights get lvl 20 defense mastery, each lvl of the mastery only gives 3-4 p def which seems barely noticeable but has a cumulative effect). This means that their physical defense is not as good as Knight or Soldier, and barely stronger than the less exposed long-ranged classes. Despite this low level of defense the assassin is usually requested to chip during Dungeon Parties. To help them survive a few hits, higher-enchanted, expensive armor is recommended and will allow the Sins' p.def to be better than average sin.
The Assassin class requires forethought and quick reactions in attacking (thus its name) as well as when attacked (ambush, field boss respawning)
Assassin Impact has a cool down of 10 minutes and a buff time-limit of 5min with out cards to make the cool down shorter and the buff longer, can make the damage out put far less than what it used to be.
Assassins use the two lowest p.atk weapons in the game; daggers and/or swords. As a result, at a basic enchant level (+3) they will not do as much damage either using skills or basic attacks, however, to obtain a higher enchant level involves risking your own weapons breaking, buying higher-enchanted weapons when you have the rupees, or using a Basic or Elite mystic jewel and shard (which again costs rupees/gen points in the case of basic jewels).
Assassin Impact - dual wield only (swords/dirks), chance of two attacks instead of one with basic attacks. Higher levels of this skill are needed to compensate for the 20% dual-wield penalty. Does not stack with other bonusses.
Cloak of Shadow - Allows the Assassin to vanish from sight for 1 minute, but the cool-down for the ability is only 30 seconds, which allows them to effectively have indefinite invisibility. Mobs are able to detect cloaked assassins when they get close. Any action will uncloak you, apart walking.
Apocalypse - dual wield only (swords/dirks). One of two AOE skills for assassin Class. 9 hits in a very small radius around the character which raises threat through damage done. Long animation.
Deadly Dancing - dual wield only (swords/dirks). Damage can be on par with Apocalypse except is target on a single mob/player.
Fatal Wave - AOE skill. Does high damage. Will only AoE in the direction the wave is thrown. Requires some practice.
Bloody Blade - Dual/Single/Two Handed Sword. Damages and Pulls HP from Target. Higher levels of this will allow you to farm regular field mobs, lower levels will bring nothing noticeable. Careful, it can fail.
Dark Strike - Dual/Single/Two Handed Weapon. 3 hits as once. Does high damage.
Head Breaker - Dual/Single/Two Handed Weapon. Causes damage and has a chance to Fear the target for 14 seconds. Careful, it can fail, and it is not instant to cast.
Charge Stab - Low Mana Cost, Fast Cool-down. Useful in DP to quickly strike a mob.
Concentration- Increases Accuracy. Allows assassins to hit mobs/players much higher than their own level.
Shadow Rush - Assassin will move hyper fast across good distances to stun target. Used to be an excellent skill despite his long CD, now almost useless as it keeps failing and the stun lasts not even two seconds.
Shadow Wound - Must be cloaked. Once cast on target, will force assassin out of cloak, cause damage, add a damage-over-time effect and cause target to lose accuracy (40% at max level) for a short period of time.
Sudden Rush- Assassins base movement speed increases by 50% for short duration which allows long distances to be covered much faster. High cool down time on this.
Blinding Dust - Blind effect on target, basic attacks of mob/player sealed.
Sonic Cross - Dual Wield. Damages target with a chance to Stun in one motion.
Deep Evasion - Adds around 20 points to your Evasion stat, barely noticeable as a sin has 400-600. Temporary Evasion increase. Not Broke contrary to opinion but don't rely on it.
Crimson Turbulence - Deals damage and has a chance to stun all mobs within a short range. It's AOE range is not listed on the skill description.
Strength/Vitality is the preferred build, as Assassins are melee characters and lack the HP, but there are some who profess to a Strength/Agility build. A single Dexterity stone in a build (assists with Accuracy), as well as a single Wisdom stone (assists with Stuns and Blinds) can prove useful in building assassins. Either you want to evade the blow or you want to minimize the damage, but in the end, you will want to destroy the target.
Assassins have passive and active skills for Swords/Dirks/Crossbows. However, dual wielding is a preferred method. When dual wielding remember that daggers have faster attacks but low P.Atk, and swords have a slower swing but more damage per hit. Furthermore, Assassins also have active skills which take advantage of 2 handed weapon damage, such as Dark Strike, Bloody Blade, Charge Stab, and Smite.
With any other class, weapon and armor enchanting is highly recommended. For sins it is necessary. Few assassins take advantage of their potential damage, as well as other classes, by not enchanting their weapons sufficiently. +20 enchanted swords/dirks on an assassin are the only way to inflict decent damage.
Another preferred build is Str/P.Atk. With new stones going around this build with the right equips and cards will make you one force not to be trifled with.
Sins being merely pull-slaves in DP since 7.3, the Vit/agi build is gaining in popularity.
Wolf It may be the best pet for reducing incoming damage for Assassins as its Belted stat. bonuses are +10% Agility (at lvl40) and +10% Evasion (at lvl90). With this Assassins can evade most of the attacks made by white mobs because their Agility is the highest compared to all other classes.
Skeleton Its' Belt-Card ability is Agility+10% (at lvl40) and Atk Speed+10% (at lvl90) allowing Assassins a higher dodge rate and faster attack speed. Dirks are the preferred weapon for the Sin to maximize attack speed. Skeletons are poor pets to use when farming (unless both the Sin and Skeleton are buffed) but are excellent and underrated DD's in a DP. It's highly advisable to use a dirk and hunter armor on the skeleton if it is the summoned pet; this equipment maximizes its HP and move speed.
Orc Orcs are good all-round pets and are effective first pets for starting Assassins. Their unity gives p.atk and p.def to the pet and owner and they are good DD's also- their 1 hit debuff skill reduces the targets' p.def, allowing more damage to be done (great for using Bloody Blade).
Blue Pixie This might seem like an odd pairing at first, but the BP helps an Assassin's survivability when soloing. They have the best healing abilities of any pet and a unity that allows the Assassins' mana to be regenerated at a moderate rate so that they are able to continue using their skills. This makes a noticeable difference even in dungeon parties when the healer can't get to you in time. However the BP doesn't offer much else apart from healing and if an Assassin uses one in a DP they will be expected to use it to heal themselves (and others if needed).
Octopus An odd pet, and somewhat unpopular because it's regarded as ugly by most players and it's quite different from all other tier 2 pets in terms of its' skills, equipment passives and unity. Most Assassins will use an octopus for its' life-leech buff which, combined with a fast attack speed and Sin Impact allows the Sin to recover large amounts of HP very quickly. It's unity is also effective on Sins as it allows attacks to do more damage and helps with mana recovery. However it is a squishy pet, much like a pixie.
Hawkman The hawk is simply an upgraded Orc, with better stats, unity and looks. It does more damage, can take more damage and helps the assassin do the same.
Salamander A rarely-used pet on an assassin because of its' hybrid physical/magical DD abilities and unity. It does not help the Sin defensively at all and is best used in a DP where luna chips allow it to maximize its' DD.
Unicorn A somewhat unusual main pet for a Sin but surprisingly useful. Its unity (if the JP are spent on it) gives MP which are always welcome on a warrior-class, it has a good healing spell with a fast cool-down, an excellent Blind skill and a buff which allows the Sin to move faster. Its belted stat also gives 12% agility. For farming it's an effective pet (use it like a BP) and in DP's it's a helpful assistant healer and debuffer. Also, at Evo3 (preferably lvl115) you can ride it- it gives a movement speed similar to the Quilin.
Nightmare A tier 3 version of the Skeleton, it is a great DD. It's unity gives more HP to the Sin which can be the difference between surviving a hit or dying from it. Also, at Evo3 (preferably lvl115) you can ride it- it gives a movement speed similar to the Quilin. Its first attack skill gives the Bleed effect, where the target cannot regenerate HP and takes Damage over Time- this skill is particularly useful on Bosses in a DP (the prevention of HP regen is an overlooked form of DD) and on other Sins in PVP/Siege as it uncloaks them.
Harpy An uncommon used pet on an assassin. It's a great DD but it's ranged, which isn't very useful when farming since it attacks the mob from a distance while you have to run to the mob. But it's a great pet for a sin in a DP since it speeds the assassin up when already having a high atk. speed.
Kentauros A summoned Kenta is a great DD in a DP and greatly increases the Sins' damage output in a DP. Its' unity plays to the strengths of the Sin Class and its' 1-hit debuff skill is effective at reducing incoming damage from a mob.
Angel Another odd-but-effective combo, it's unity adds p.def (more than orc, hawk or yeti) and it can heal. Its' 1-hit debuff reduces the targets' p.def and m.atk which allows more damage to be done but otherwise it does little to help the Sin DD. Possibly a good pet to use when farming (especially champ mobs) but you may get a few questions asked if you turn up to a DP with an angel!
[Death Tyrant] This is considered the absolute best pet for an Assassin as its' unity adds to P. Atk and Attack Speed. A Death Tyrant is helpful in both farming and in a DP. Note however, on an Assassin, a non-pet class, a Death Tyrant will be unable to match its abilities as when on a pet class.