The lightsaber of Star Wars fame and all weapons like it are universally accepted as one of the most awesome weapons in fiction. And the ability to create a lightsaber with your mind sounds double awesome. Hence, one day after smoking an entire market's worth of opium, someone at Wizards of the Coast thought it was a good idea to create the Soulknife for the Expanded Psionics Handbook of 3.5e Dungeons and Dragons. Unfortunately, like many before it in third edition, this did not turn out all too well...
The mindblade archetype for the magus is one Pathfinder equivalent/reworking. While it lacks the fun-factor of "Knife to the Soul," it is reasonably powerful. I mean, at least not it's not this. Dreamscarred Press would also come up with a straight port of the soulknife. While still probably the weakest of the psionic classes, it's solidly on-par with the fighter, barbarian, and other straight martial classes, and, unlike the 3.5 version, gets full BAB, better action economy, gets to pick one of three shapes for his soulknife right off the bat (longsword, greatsword, and dual shortswords, basically), and has lots of customization in the form of "blade skills," which are equivalent to magus arcana or barbarian rage powers. Sure, Knife to the Soul got a sorta-nerf, but it's still loads better and more fun to play now, and even has all kinds of archetypes and stuff. There are even ones that let you delve into The Book of Weeaboo Fightan Magic or actual psionics. Take a look.
KNIFE MIND ATTACK
The main feature of the Soulknife is its primary weapon, the mindblade(s). It is a psychically created weapon, a shortsword created from the psyche of the soulknife consisting of semisolid psychic energy. If the Soulknife lets go of it it immediately dissipates unless used as a thrown weapon, and the user can create a new weapon with ease to rearm themselves. Skilled Soulknives can split their weapon up into two blades (though it makes them slightly weaker), imbue them with up to 5d6 extra damage per strike, turn them into bigger swords (long or bastard), throw them, imbue them with enchantments normally found on weapons, attack multiple targets in one blow, damage mental stats on a target and a few other tricks. While these all seem like interesting and fun tricks... when you add them up, the class still sucks. Simply put, the Soulknife is bad. Like, Fighter bad.
First, the Soulknife is a full-on combat class, i.e. it has to get in and keep hitting people with its soulknives. The first problem with this is that the Soulknife has 3/4th BAB progression, the same as rogues, clerics, and druids. This is not good for a class meant to hit things in straight-up combat. Next up, while the Soulknife has a d10 hit die, it has only light armor proficiency (You see how the guy in the picture has chainmail? He had to blow a feat to wear it) or any class features that help defending itself, meaning that you're stuck with light armor and a shield to not die. Its lack of feats (aside from the ones you get normally) mean that even if you try to become better this way you still are very vulnerable in combat.
Next up, the Soulknife is kind of slow to utilize. Until level 5 drawing your Mind Blade is a move action, as is imbuing it with Psychic Strike. So if you want to deal some serious damage at lower levels you've got a bit of a problem. If you manage to live that long you'll become able to make your blades better by turning them into longswords of bastard swords... but this takes a full round action, leaving you doing nothing. At this point you'll also start to notice that the rest of your party starts to swing around +2 weapons when you just got your first +1 bonus last level. And at the end of the day you're still only swinging around a shortsword, whose d6 damage just does not hurt. And at the point where it gets better, pound for pound you still deal less damage than your party's Fighter.
At higher levels Knife to the Soul becomes interesting, given that you can combine it with multiple throwing attacks. This means that you can throw four knifes who each deal 3 damage to one characteristic of your choice, which might net interesting results when you start to damage Wizards and drain their spells, or defeat a monster in one go with a well-placed throw. The obvious downside to throwing its that it's only got a 30 feet range, putting you into trouble when facing long-distance enemies.
Another problem with the Soulknife is that its skills kind of suck: they're all over the place. There are a couple of DEX based skills (hide, move silently, tumble) and the useful Autohypnosis, Concentration and Knowledge (Psionics) that you don't see on other classes... but those are spread out over four different attributes. For the rest you have the standard package of skills, so you can't do something interesting with this.
There is a prestige class for the Soulknife called the Soulbow in Complete Psionics, and notoriously one of the few decent things in a book full of crap (which is why Wizards of the Coast chose to release it for free as a preview). It allows you to create arrows just like you create your knifes and shoot people with it from a safe(r) distance. This sounds meh... until you realize that while in combination with Zen Archery WIS is pretty much the only stat you need for this prestige class but it does zero good for your levels of Soulknife, your bow kind of sucks (a regular composite longbow that cannot be upgraded), the upgrades for your arrows just kind of stop at a certain level, and Phase Arrow (shoot through pretty much anything) is not really worth it. There's a few thing that make it far and away better than the base classes though. Firstly because you only need one hand to shoot a mind arrow you can use two-weapon fighting and rapid shot to spam a lot of attacks a turn. Lastly, on the abilities you can add to your arrows is Lucky, for a mere +1 bonus. Lucky lets you reroll an attack with that weapon once per day, which doesn't sound too great till you realize each arrow is it's own weapon so you can reroll all your attack rolls which more than makes up for your terrible base attack bonus (and many penalties from TWFing with rapid shot). Combined these can get a bit unwieldy during actual play though, as you can be rolling to-hit 10 times or even more every turn and as order is actually important you can't roll them all at once (A sane GM will let you roll different colored d20 for the initial attacks, but this doesn't solve the reroll issue). Plus all you'll ever do in combat is full attack.
In short, the only two ways that a Soulknife can kinds work is either as a Fighter but worse (far less attack feats and such), or as a knife-throwing machine that'll fold like wet paper when hit and wastes everyone's time with a ton of die rolls. Which is sad, because its concept is very fun.
After effectively being non existent for an edition, the Soulknife was recently added to 5e via playtest for the mystic class. Unfortunately, it appears the designers have decided that it must continue the class's longstanding tradition of being fucking terrible, with no unique disciplines, no extra level one disciplines, no extra attacks, and incredibly low damage for a class whose entire schtick is supposed to be doing damage with psionic mind-blades.
With the advent of Dreamscarred Press' Psionics line, the psionics system of the D20 system got a major overhaul and improvement. As a side effect, the Soulknife became a lot better and more fun to play. For starters, the Mind Blade itself can be either two light weapons perfect for throwing, a one-handed weapon to use with a shield or a two-handed weapon for extra damage (note that the Half-Giant from the same book can Mind Blades that are one size larger than he is thanks to their special features). On top of that, the Mind Blade can be either Slashing, Piercing or Bludgeoning so you can make a SOUL HAMMER. The blade also remembers this when it vanishes, and reshaping it takes a single full round. The blade enhancements have also been revamped: the increased damage enhancement and special effect tracts have been combined, starting at 3rd level and increasing to a total pool of +9 at level 19. Reshaping the blade requires either an 8 hour rest or concentrating for 8 hours, so make sure to plan ahead. Psychic Strike still works more or less the same, except both blades have the same enhancement if you have two of them, the effect only triggers when you want to and affects all creatures with an Int score (so suck it, vampires!) and it can be charged with a Psionic Focus. Throw Mind Blade and Quick Draw are still there, and the capstone ability, making it very difficult to lose your Mind Blade to anti-psionics effects, is a bit lacking. At least you get to reconfigure your blade in a full-round action instead of 8 hours.
New to the Pathfinder version are the Blade Skills, gained at every even level. These are the special tricks you see on several Pathfinder classes, like the Barbarian and Rogue. These grant a variety of bonuses improving your Mind Blade and how you use it. Possible bonuses include elemental damage, Reach, Trip, more Psionic Charges, 5-foot steps and even the ability to expend your Psychic Strike to stop any spell, power, SLA or PLA thrown at you (but not Supernatural Abilities), letting you slap aside Fireballs, Disintegration, Meteor Swarm and what have you. Some of thse are far better than others, but there's enough good stuff in there.
The Soulknife also gets a number of Archetypes. These include Armored and Shielded Blade (create armor and a shield just like a Mind Blade at the cost of making your weapon less powerful; use both for some stellar AC at low levels), Cutthroat (Sneak Attack instead of Psychic Strike, also more sneaky abilities), Deadly Fist (supercharged fists), Nimble Blade (get the most out of a Dex-build Soulknife) and the Soulbolt (the Mind Blade becomes a blast of energy instead, basicly Soulbow that works). Of particular note are a pair of archetypes that entirely replace Psychic Strike: The Gifted Blade archetype, which gives you Paladin/Ranger tier psionic manifesting, and War Soul, which gives you access to The Book of Weeaboo Fightan Magic and the ability to turn your mind blades into working guns.
Overall, Pathfinder's Soulknife is a lot more fun to play with a lot more options, meaning that your KNIFE MIND ATTACK is actually useful instead of a novelty.
|The Classes of Pathfinder|
|Core Classes:|| Barbarian - Bard - Cleric - Druid - Fighter - Monk |
Paladin - Ranger - Rogue - Sorcerer - Wizard
| Arcanist - Bloodrager - Brawler - Hunter - Investigator |
Shaman - Skald - Slayer - Swashbuckler - Warpriest
| Alchemist - Antipaladin - Cavalier |
Inquisitor - Oracle - Summoner - Witch
| Kineticist - Medium - Mesmerist |
Occultist - Psychic - Spiritualist
|Ultimate X:||Gunslinger - Magus- Ninja - Samurai - Shifter - Vigilante|
| Aegis - Cryptic - Dread - Marksman |
Psion - Psychic Warrior - Soulknife
Tactician - Vitalist - Wilder
|Path of War:||Harbinger - Mystic - Stalker - Warder - Warlord - Zealot|