Duskblade

The Duskblade is a character class for 3rd Edition D&D that can be found in the Players Handbook II.

The class itself is very similar to the Hexblade character class; being a martial class with access to INT based, spontaneous arcane spellcasting. The Pathfinder equivalent is the magus, and the Hexblade is an archetype of the same.

It beats out the Hexblade in that it has better saves, earlier access to spells that continue on to a higher level, learns how to cast spells while wearing up to medium armour and the Duskblade is not bound to a non-good alignment. By contrast the Hexblade has better hit dice and is much more of a pain in the ass to fight against due to his curses.

The Duskblade spell list is quite limited, restricted to only damage dealing or buff spells. Which is perfectly fine since your party should already include a dedicated caster. Though when you get to the higher levels, you get to be able to cast a phenomenal 10 spells per day of 1st-3rd level spells.

Compared to a dedicated fighter though, you miss out on raw killing ability, since nearly all of the class features of the duskblade are focused towards improving their spellcasting. Though one cool ability later in their progression is the ability to just cast a touch spell as part of the attack actions, so they don't have to worry about casting defensively or holding it for a turn while waiting for someone to discharge it onto. They can even discharge touch attack spells against multiple targets if they know feats like Whirlwind Attack for horde rape.

Despite this, like many of the hybrid warrior-classes, they fit firmly into the second rank of fighting classes and make an extremely effective support warrior for your party's barbarian, fighter or paladin.

Making it Work

Prestige Class options for Duskblades should be looking into making them more killy and not into dedicated spellcasters; they'll just never cut it as the party's main caster.

So moving into warrior prestige classes is totally up to the player, as there are a multitude of different fighting styles all helpful to Duskblades, but generally sacrifice further spellcasting ability.

That said, prestige classes which continue to improve their spellcasting are helpful only if they have progressed far enough as Duskblades to earn the early class abilities which continue helping him at higher levels.

Unfortunately, several of the "hybrid" prestige classes are actually worthless to a Duskblade, as they tend to provide you with abilities that you already had. Such as the Bladesinger or Spellsword, so avoid these as you get nothing out of them.

Abjurant Champion from Complete Mage works well by continuing your BAB and spellcasting progression fully. It also lets you "burn" uncast spells to give yourself temporary boosts, which can be handy considering the sheer number of spells you get to cast per day. But also it final ability really helps you out by allowing to take your caster level in a chosen class as your base attack bonus (unless your BAB is higher). The implication here is that after you have completed this 5 level prestige class you can move into any other poor BAB / good spellcasting class, and maintain your top rate BAB by choosing Duskblade as your chosen casting class.

Green Star Adept works alright, it is qualified for very easily and it is useful to the party in that it turns your character into a brick. Though it does reduce both your spellcasting and attack bonus by about half. But again can be countered by becoming an Abjurant Champion and maintaining your top attack bonus. (yes, the class gains spells-per-level are only every other level, the first class feature improves your overall caster level by the class level)

Scion of Tem-Et-Nu from Sandstorm applies all on its own without needing assistance from the Abjurant Champion, and turns your character into a sort of River Paladin-lite. Although much of this class is situational, and it depends on your GMs particular view on the campaign setting.

If your character takes one class-level (or several feats) from the Tome of Battle then you can easily qualify for the Jade Phoenix Mage class. Which is actually pretty awesome since you can convert your buttload of unused spells into extra damage and gain additional stances and abilities which remarkably improve your fighting abilities, which when put together with Duskblade abilities can lead to Cheese-like levels of power.