This is meant to demonstrate how with a slight narrative reframe, we can be faithful to the original setting while updating it to 3.5E.
Athasian Assassin AKA “the bard”
Athas is a place rife with assassins and assassinations. Assassins are employed by Sorcerer-Monarch, templars, the Veiled Alliance, and ordinary citizens with a score to settle. Because assassins in the Dark Sun setting are very good at pretending to be something that they are not, quite often musicians or singers, they are colloquially referred to as “bards”. While “bard” means musician or singer in common tongue of the Tyr region, it carries strong cultural and historical context of assassins pretending to be singers. Therefore, when one says, “I’ll hire a bard”, it always means hiring an assassin. If someone wants to hire a musician, then they say “musician”, not bard.
Athasian assassins are skilled at embedding themselves in positions of trust, from which they carry out their assassinations. All assassins are able to construct cover identities, which could be a baker, a servant, or indeed, a singer or musician.
Hit Die : d8.
To qualify to become an assassin, a character must fulfill all the following criteria.
Alignment : Any evil.
Skills : Disguise 4 ranks, Hide 8 ranks, Move Silently 8 ranks.
Special : The character must kill someone for no other reason than to join the assassins.
The assassin’s class skills (and the key ability for each skill) are Balance (Dex), Bluff (Cha), Climb (Str), Craft (Int), Decipher Script (Int), Diplomacy (Cha), Disable Device (Int), Disguise (Cha), Escape Artist (Dex), Forgery (Int), Gather Information (Cha), Hide (Dex), Intimidate (Cha), Jump (Str), Listen (Wis), Move Silently (Dex), Open Lock (Dex), Perform (Cha), Search (Int), Sense Motive (Wis), Sleight of Hand (Dex), Spot (Wis), Swim (Str), Tumble (Dex), Use Magic Device (Cha), and Use Rope (Dex).
Skill Points at Each Level : 4 + Int modifier.
Weapon and Armor Proficiency : Assassins are proficient with the crossbow (hand, light, or heavy), dagger (any type), dart, rapier, sap, shortbow (normal and composite), and short sword. Assassins are proficient with light armor but not with shields.
Sneak Attack : This is exactly like the rogue ability of the same name. The extra damage dealt increases by +1d6 every other level (2nd, 4th, 6th, 8th, and 10th). If an assassin gets a sneak attack bonus from another source the bonuses on damage stack.
Cover Identity (Ex): An Assassin is rigorously trained to establish nearly flawless cover identities. For every distinct Perform skill in which she has at least 2 ranks, she may have one cover identity. Each cover identity must be a specific person (such as “Mattias Zambrik, castrati singer of Balic”), not a generic description (such as “singer”). She may at any time end an existing cover identity and establish a new one in its place.
While operating under any of her cover identities, she gains a +4 circumstance bonus on Disguise checks and a +2 bonus on Bluff and Gather Information checks. For each additional 2 ranks (beyond the minimum 2) that the Assassin possesses in a cover identity’s associated Perform skill, each of these bonuses increases by 1. At the DM’s discretion, these bonuses may be reduced or eliminated in regions where the cover identity would seem out of place (a templar from Tyr, for example, would attract suspicion in another city-state).
Establishing a new cover identity or replacing an old one means the Assassin must acquire documentation and personal effects, establish a place of business, and otherwise set up a believable second life. This process takes 1d4 tendays, during which she may do nothing else, and costs 6d10 cp. The Assassin does not need to set up a cover identity immediately for every Perform skill in which she has 2 ranks; she may wait until a good opportunity presents itself if desired.
The cover identity ability does not provide any additional skills that might be necessary to make a cover identity believable, such as knowledge of the proper homeland, the ability to speak a foreign language, spellcasting ability, or the like. Thus, Assassins generally pick cover identities that complement their existing skills.
Uncanny Dodge (Ex) : Starting at 2nd level, an assassin retains his Dexterity bonus to AC (if any) regardless of being caught flat-footed or struck by an invisible attacker. (He still loses any Dexterity bonus to AC if immobilized.)
If a character gains uncanny dodge from a second class the character automatically gains improved uncanny dodge (see below).
Death Attack : If an assassin studies his victim for 3 rounds and then makes a sneak attack with a melee weapon that successfully deals damage, the sneak attack has the additional effect of possibly either paralyzing or killing the target (assassin’s choice). While studying the victim, the assassin can undertake other actions so long as his attention stays focused on the target and the target does not detect the assassin or recognize the assassin as an enemy. If the victim of such an attack fails a Fortitude save (DC 10 + the assassin’s class level + the assassin’s Int modifier) against the kill effect, she dies. If the saving throw fails against the paralysis effect, the victim is rendered helpless and unable to act for 1d6 rounds plus 1 round per level of the assassin. If the victim’s saving throw succeeds, the attack is just a normal sneak attack. Once the assassin has completed the 3 rounds of study, he must make the death attack within the next 3 rounds.
If a death attack is attempted and fails (the victim makes her save) or if the assassin does not launch the attack within 3 rounds of completing the study, 3 new rounds of study are required before he can attempt another death attack.
Poison Use : Assassins are trained in the use of poison and never risk accidentally poisoning themselves when applying poison to a blade.
Bonus Feats: At 5th and 9th level the assassin gets a bonus feat from the list of fighter bonus feats for which it qualifies.
Assassin Skill Mastery (Ex): An assassin is so confident in the use of assassin class skills (selected from the skills of this prestige class) that she can use them reliably even under adverse conditions. She selects a number of skills equal to 1 + her Int modifier. When making a check with one of these skills, she can take 10 even if stress and distractions would normally prevent her from doing so. Each time an assassin gains a class level, she can add another skill to the list of skills with which she has mastery.
Save Bonus against Poison : The assassin gains a natural saving throw bonus to all poisons gained at 2nd level that increases by +1 for every two additional levels the assassin gains.
Fast Movement Ex): At 3rd level, an assassin’s land speed is faster than the norm for his race by +10 feet. This benefit applies only when he is wearing no armor or light armor and not carrying a heavy load. Apply this bonus before modifying the assassin’s speed because of any load carried or armor worn.
Improved Uncanny Dodge (Ex ): At 5th level, an assassin can no longer be flanked, since he can react to opponents on opposite sides of him as easily as he can react to a single attacker. This defense denies rogues the ability to use flank attacks to sneak attack the assassin. The exception to this defense is that a rogue at least four levels higher than the assassin can flank him (and thus sneak attack him).
Hide in Plain Sight (Su) : At 8th level, an assassin can use the Hide skill even while being observed. As long as he is within 10 feet of some sort of shadow, an assassin can hide himself from view in the open without having anything to actually hide behind.
He cannot, however, hide in his own shadow.
Ranged Death Attack (Capstone Ability): By studying your opponent twice as long as normal, you are able to make a death attack with a ranged weapon.
If you study a potential death attack victim for 6 rounds, you are able to make a death attack against the victim using a sneak attack with a ranged weapon that successfully deals damage. As normal, the target must be within 30 ft. in order for the attack to be a sneak attack.
You may not use this ability in conjunction with abilities which reduce the number of rounds that you must spend studying your victim.