I'm starting a new D&D campaign. I'm still fairly new to D&D and I want to build a Rogue/Assassin that dips into Swordsage for the assassin stance. I have read on other sources that this is the best option. I want my character to be high damage output and always be behind the enemy. My DM has given me access to all 3.5 material to play with. How would I go about building this character?
First, a quite analysis on assassin’s requirements and features
8 ranks in each of Hide and Move Silently mean you’ll need to be at least 5th level, since your ranks are limited to level+3. Otherwise, entry is easy.
1d6 on each odd level; that’s as good as a rogue, which is as good as it gets. Solid.
Rarely useful; death attack takes too long to set up, many targets are immune to death effects, and the DC is kind of mediocre unless you have a lot more Intelligence than you’re likely to have.
Completely useless; poison can be OK, but if you want to use poison, you need Master of Poisons from Drow of the Underdark, which allows you to poison a weapon as a swift action. It also includes Poison Use as part of its features, so you’d get this anyway.
Not bad, not amazing.
Save bonus vs. poison
Poison doesn’t really get used all that often, but at least it’s a bonus to a save you aren’t great at.
Hide in Plain Sight
Takes far too long to get, but this is quite good. So long as you’re not in an antimagic field, you can almost-certainly hide just about anywhere.
These are the big win. Spellcasting is the best ability in the game, and with Spell Compendium, assassins actually get some nice unique effects.
Other relevant classes
As a 10-level prestige class, assassin demands that you spend at least 10 levels elsewhere by 20th, and since you can’t enter before 6th, at least 5 levels prior to starting your assassin career. Here are some thoughts.
The obvious entry, and not an awful one. The biggest advantage of rogue comes at 2nd, when you can take the penetrating strike variant from Dungeonscape. This allows you to deal half your Sneak Attack damage when flanking things that are normally immune to it.
Still, aside from this, all rogue is offering is Sneak Attack and a boatload of skill points. Not necessarily your best option.
This class from Tome of Battle is excellent, and can get you access to a number of features. Ideal levels to take it are 5th (netting cloak of deception for swift-action invisibility during your own turn, shadow jaunt for a 50-ft. teleport, and mountain hammer for ignoring DR and hardness), or 9th level (getting all of that, and also the assassin’s stance you mention). If you take it at 5th, you can still take the Martial Stance feat at 9th to get assassin’s stance. While we’re on the subject of stances, island of blades may be even better for you than assassin’s stance, and you can take that at any level since it’s a 1st-level stance.
Or just take it single-classed for the first five levels, netting assassin’s stance at 5th instead of 9th. That way, you also get Wisdom-to-AC, even in armor (up to light); ask your DM if you can take the Kung-Fu Genius feat from Dragon Compendium to switch this to Intelligence.
Fighter is pretty mediocre, but there are enough variants out there to make it worthwhile enough. Drow of the Underdark has the excellent hit ‘n’ run tactics variant, which trades medium and heavy armor proficiency, as well as shield and tower shield proficiency, for Dex-to-damage against flat-footed foes and +2 to Initiative.
Unearthed Arcana has a sneak attack variant, which gets sneak attack as a rogue instead of bonus feats; rogue is almost-certainly better but if you needed full BAB and full sneak attack for some reason it could be an option. The thug variant gets slightly more skills, too, and is compatible with the sneak attack fighter.
This class from Complete Warrior gets Weapon Finesse as a bonus feat at 1st level, can swap grace for arcane stunt from Complete Mage at 2nd, and at 3rd level gets the insightful strike feature, adding his Intelligence bonus to damage. That’s literally the beginning and the end of swashbuckler as a useful class, but those are decent enough features. Arcane stunt, for the record, allows you to get a 1-round, swift-action usage of one of several spells, most of which are garbage but one, blur, decidedly is not.
You could alternatively take Daring Outlaw from Complete Scoundrel to stack swashbuckler with rogue for Sneak Attack, but that requires not using arcane stunt. An extra 2d6 Sneak Attack damage isn’t terrible for a feat, but it’s not great. You also get a half-power Dodge feat out of it, but Dodge is an awful feat and half-power is just not worth remembering to use.
The Complete Adventurer ninja is pretty mostly awful; just mentioning it for completeness’s sake. Two levels for ghost step is valid enough, I suppose, but sudden strike is much worse than sneak attack.
There is a variant in Dragon vol. 354 that trades ghost step for obscuring mist that you are immune to. That’s really quite good. If you were focusing on poisons, the 8th-level upgrade lets you deliver one through the mist, which is... cool, and half-decent since it applies one poison to everyone in the cloud (except you), but poisons tend to be rather lackluster at this level. The 10th-level upgrade, though, is incredible, turning the mist into solid fog. Solid fog is one of the more devastating battlefield control spells. But 10 levels is just way too much for this feature.
Now we’re getting somewhere. Factotum from Dungeonscape adds Intelligence to most everything, most importantly all Strength- and Dexterity-based ability and skill checks. That includes stuff like Hide and Move Silently, and also Initiative. This is not a replacement, either, so this is on top of your Dexterity (or Strength).
The factotum also gets all skills in-class, which is rather nice. This includes Iaijutsu Focus from Oriental Adventures, which works kind of like sudden strike, but only immediately after drawing a blade. The gnomish quickrazors from Races of Stone are an exotic weapon that are sheathed after every attack, allowing you to constantly apply iaijutsu, but you still need a flat-footed target which is not trivial.
One level can get you whirling frenzy and Pounce with the lion spiritual totem from Complete Champion. Another attack and the ability to move and attack at the same time are both clutch for you.
One level gets you Travel Devotion, using Complete Champion’s domain-replacing rules. Travel Devotion is even better than Pounce for you, giving you mobility you badly need. You also get some other domain or devotion, plus Turn or Rebuke Undead, which can be used for divine feats. Notable example: Lolth’s Caress from Drow of the Underdark makes everyone in a certain radius who is suffering from poison, take the secondary damage immediately.
If you use the cloistered variant, you also get Knowledge Devotion, which is +1 to attack and damage for sure, and more if you can make decent Knowledge checks against your foe. Also, 6+Int skills, which is nice. If you have at least 11 Wisdom, you can also use identify as a divine spell, which means there’s no 100-gp arcane material component.
This prestige class from Dragonmarked requires that you be a halfling and take the Mark of Hospitality, and has a number of poison-related features. It also stacks with assassin for death attack DCs, which would be awesome if it weren’t for death attack’s inherent problems.
Basically, Small-sized humans from Forgotten Realms Campaign Setting (actually, they trade the halfling save bonus for a bonus feat). Small size is an advantage to you, since most of your damage comes from sneak attack anyway. The bonus feat is huge. Also works out nicely for black dog entry.
Close to the quintessential stealth race, whisper gnomes from Races of Stone are small, get a number of stealth bonuses, and have some spell-like abilities that are quite useful. Could take Weapon Familiarity to get proficiency in gnomish quickrazors instead of Exotic Weapon Proficiency, netting proficiency in other gnomish weapons too (like the gnomish calculus! I swear this is a real thing, from Arms & Equipment Guide. It flings alchemical weapons).
Kobolds playing to their strengths
Double down on the benefits of being Small by being Small and having the slight build feature. The stealth bonuses are massive (+8), and having built-in weapons doesn’t suck. Consider the Dragonwrought feat from Races of the Dragon for a number of unreasonable benefits, like immunity to age penalties (be Venerable for a free +3 to all mental stats!). Actually, talk to your DM about that one cuz he may want to ix-nay it.
This race from Eberron Campaign Setting gets the ability to change their appearance at will. The Disguise bonuses are, unsurprisingly, rather large. Moreover, the changeling rogue variant from Races of Eberron get 10+Int skill points at 1st (i.e. 4×(10+Int) for a lot of points if you take it as your first class level). They also get a number of useful features with social skills. Makes for a rather different sort of assassin.
There are several feats worth considering as an assassin.
You want Dexterity for a whole lot of things. Using this applies it to your attacks, so you don’t need to worry about Strength for accuracy. Swashbuckler gets it as a bonus feat at 1st.
As Weapon Finesse, but for different weapons (Shadow Hand associated weapons), and for damage instead of attack. Counts as Weapon Finesse, but you can take both. Requires you be in, and maintain, a Shadow Hand stance. Island of blades is the clear winner for 1st-level stance; when or if you get 3rd-level stances, *assassin’s stance is competitive. Both work for this, though.
You get bonus damage; this is how you get to apply it more often. Feat-intensive, so keep in mind that gloves of the balanced hand from Magic Item Compendium can give you this feat, or if you already have it, Improved Two-Weapon Fighting.
From Lords of Madness, this eliminates a lot of the “automatic” ways of foiling your stealth, forcing people to use Spot vs. your Hide or Listen vs. your Move Silently. That’s a very big deal.
Add your level to your damage every time you make a sneak attack. That’s a dramatic improvement (a single-classed rogue is effectively adding 1¾×level to damage from sneak attack, so another 1×level is a substantial improvement). Requires that you not be immune to fear, however, and applies a −2 penalty to saves against fear, which is bad. Consider it carefully. It’s a much better feat early than it is later, since early on there aren’t many options for getting fear immunity anyway, while later on you’ll desperately want it.
Some concepts you might want to consider.
Swordsage 5/Assassin 10
About as simple as they come, and solid. Whisper gnome is probably the best race, though any are competitive. Key feats are Shadow Blade, Weapon Finesse, Two-Weapon Fighting, and Darkstalker. Note that swordsage does not get Disguise as a class skill; that means you either take it cross-class (paying 8 skill points to get the 4 ranks you need), or you do something to get it in class. Since getting 4 cross-class ranks doesn’t delay you any, 4 lost skill points seems much cheaper than anything you could do to get Disguise in-class short of a houserule.
Definitely grab mountain hammer at 3rd or 4th. In fact, since you want that and cloak of deception and shadow jaunt, Martial Study for one of these might be a decent idea at 3rd or 6th. Island of blades is almost-certainly your 1st-level stance, and assassin’s stance likewise at 5th. The other probably won’t matter as you’ll pretty much always be using one of these. I like step of the wind for when you need to traverse annoying ground.
Ask the DM about Kung Fu Genius applying to swordsage class features instead of monk ones. Even if only hits the AC bonus, that’s solid. If it gets the swordsage’s insightful strike, that’s awesome.
A variant on the above:
Swordsage 5/Assassin 3/Jade Phoenix Mage 10
Basically, JPM from Tome of Battle advances maneuvers and spellcasting. Assassin is an unusual choice for that, to be sure, but it does have some unique things going for it. Your death attack DC will be useless, but then death attack isn’t much better than useless anyway.
Rogue 2/Factotum 3/Assassin 3/Swordsage 1/Assassin +7
Human or human-descended becomes key here, for Able Learner from Races of Destiny. Note that changelings are human-doppelganger hybrids, which makes them an option for their excellent Races of Eberron racial substitution level. Penetrating strike at 2nd is a must. Dip swordsage at 9th to get assassin’s stance. Consider Shadow Blade at the same time, or Martial Stance for island of blades.
Important feats include the usual suspects, above, but also Able Learner and Exotic Weapon Proficiency (gnomish quickrazor), for Iaijutsu Focus. This adds another dimension to your damage. In addition, Font of Inspiration may be worthwhile to add Int to attack more often.
A variant on the above.
Factotum 3/Swashbuckler 3/Assassin 2/Swordsage 1/Assassin +8
Intelligence to everything but attack, Dexterity to attack and damage, and Int-based spellcasting. Definitely solid. As long as we’re here, ask your DM about swordsage and Kung Fu Genius, for Int to that too.
Rogue 3/Barbarian 1/Swordsage 1/Black Dog 5/Assassin 10
From this answer, to a question asking for a prestige class for a stealthy barbarian/rogue. Barbarian makes you a whirling frenzy of blades, black dog makes you handy with poisons and adds to your death attack DC, so at DC 25+Int it stands a decent chance of working if you do manage to pull it off.
Strongheart halfling is pretty much the necessary race because of the need for Mark of Hospitality. Master of Poisons is key to making it work.