I remember trying to make a fighter/wizard combination back in my 3rd Edition Dungeons & Dragons days, but aside from houserules and/or specialized builds (requiring classes, prestige classes, feats, and/or magic items) it doesn't work, and I'm not even sure about the latter.
This is because of all the fiddly math in 3rd Edition: fighters need all those plusses to hit in order to hit things (with the first attack, anyway), and spellcasters need higher level spells because the saving throw numbers are based on the spell's level, so lower level magic quickly becomes worthless.
Something else I disliked about 3rd Edition was that, by the book, if you're a wizard and multiclass into fighter you immediately become proficient with all weapons and armor. Of course that's not as ridiculous as a fighter multiclassing into a wizard and being able to immediately cast spells, get a spellbook with a bunch of spells, and being able to snag a familiar.
4th Edition made things less silly with multiclass feats: you spend a feat in order to basically get a single spell, which makes more sense then a shitload somehow. Problem is by the books you can't really evoke both classes because there's only three multiclass feats, so you can only ever have three powers from the other class.
I think hybrid classes might have made this easier (ability scores could be a problem because the game assumes a +3 or +2 base for your "attack" stats), but I never bothered with them much so can't say. Really if you wanted to do a fighter/wizard proper without houserules, you're better off just rolling up a swordmage or bladesinger.
With Dungeons & Delvers: Black Book we wanted to allow flexibility and mitigate multiclassing issues/nonsense: right now if you multiclass into another class you don't gain weapon and armor proficiencies or saving throws, or the WP/VP it gets at 1st-level (you get the level-up amounts which are smaller). You usually don't gain all of the class features (MC fighters get +1 to hit and damage, but wizards and clerics lose out on an extra talent or two).
So using the alpha multiclassing rules (which got added as an extra download over on DriveThruRPG), here's what a 1st-level human fighter/1st-level wizard looks like if you started the game as a fighter:
SPELLSWORD (Fighter 1/Wizard 1)
Level 2 Medium Humanoid (Human)
Speed 30 feet
STR +2 DEX +0 WIS +0
CON +1 INT +2 CHA -1
Arcana +5, Athletics +3, Search +3
Speed 30 feet
AC 12 DR 2 (scale armor)
Fort +2 Ref +0 Will +0
Wounds 10 Vitality 5 Total 15
Arming Sword: +3 to hit; 1d8+3 damage (critical hits on 19-20)
Magic Missile: +3 to hit; 1d6+2 force damage
Evoker: 1d4 Drain; target suffers 3d6+2 force damage (half on DC 13 Reflex save)
arming sword, scale armor, magic focus (probably a wand or staff), explorer’s pack
So you're not as tough as a 2nd-level fighter (something like 2 WP and 1 VP behind), and you don't get a fighter talent (which could give you added defense, damage, a special attack, and so on). The plus side is, hey, you got a pair of magic attacks (albeit you need a hand free to use them) and you can detect magic (though I might drop auto-detect magic and make it part of the Divination tree).
If you want a bit more magic, you can instead go with the elf race since it has an option to gain a magic talent and +4 Mana:
SPELLSWORD (Fighter 1/Wizard 1)
Level 2 Medium Humanoid (Elf)
Speed 40 feet
STR +1 DEX +2 WIS +0
CON +0 INT +3 CHA -1
Arcana +5, Athletics +2, Search +4
Speed 40 feet
AC 14 DR 0 (Abjurer talent)
Fort +1 Ref +2 Will +0
Mana 6/8 (sustaining Abjurer)
Wounds 8 Vitality 5 Total 13
Short Sword: +3 to hit; 1d6+3 damage
Magic Missile: +4 to hit; 1d4+3 force damage, and target must succeed on a DC 14 Fortitude save or be knocked prone
Evoker: 1d4 Drain; target suffers 3d6+3 force damage (half on DC 14 Reflex save)
arming sword, magic focus (probably a wand or staff), explorer’s pack
I like the differences between both characters: the human is stronger and tougher, while the elf is faster and can better rely on magic for defense (though he doesn't have the DR that the human does). In either case I think they'd both work out just fine.
I actually tried doing a fighter/wizard that starts out as a wizard, but the end result was you're best served using the Shocking Grasp cantrip for melee attacks and Magic Missile for ranged attacks, only switching to a repeating crossbow if the target has high DR because it has armor piercing 2.
The human ended up burning through all of his Mana sustaining Abjurer and Mage Armor (which is why I went with talents that had good cantrip effects), while the elf had 4 points left over, which is enough to use Evoker or Shocking Grasp now and again. I suppose you could focus entirely on Abjurer or Illusionist, but humans have a sparse weapon selection (elves have auto-proficiency with arming swords and so have a solid d8-damage option).
I still think it'd be a neat and functional character, but not what I think when I think "spellsword".
We're considering adding in talents that let you become proficient with weapons and armor. I initially wanted to make them free aside from time and money to train in them, but I could see every wizard just doing that because there'd be no downside. This way it'd be a choice. Could also restrict it to certain classes so you need to multiclass out in order to snag them, so wizards that want to be able to wear armor would lose out on some magic juice.
Adam is working on rules for hybrid classes, because he's a huge fan of 4E hybrids and I think it'd be great to let players mash up a couple classes instead of waiting for/cobbling together a specific class. When that's good to go I'll add it as an Appendix D PDF.
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