I'm new to D&D, and currently playing as half-elf lvl 5 fighter. I took the "two weapon fighting" and "Dual wielder" feats. My ability scores are:
Str: 8 (-1)
Dex: 16 (+3)
Con: 16 (+3)
Int: 8 (-1)
Wis: 14 (+2)
Cha: 12 (+1)
I have 18 AC when using two weapons, and as weapons I am using two rapiers because they are finesse weapons. I have the battle master archetype, and currently I have Pushing attack, Goading attack and Trip attack.
At level 5 I have noticed that my attacks are not so strong as, say, our paladin's attacks. He deals 40-50 damage each turn. Our archer (ranger) deals like 30 dmg each turn. But I deal like 25 damage in a turn, even if I use my Action Surge.
Is this just how dual fighters work or is this me doing something wrong (either in terms of calculating how things add up or in terms of the choices I made when building the character)?
Best Answer
You are making a few mistakes in your build, and in your analysis
You calculated some things wrong, and also your character is not optimally built.
Calculation
You have compared your average damage with the nova damage of the Paladin. A 5th level Paladin cannot do 40-50 damage on each of his turns; only when he decides to spend a spell slot on Divine Smite. This is a finite resource, and he has only 6 of those on level 5.
If he uses Great Weapon Master, it greatly decreases his hit chance, and yet you only compared the rounds when you both hit with every attack. This distorts the calculation.
Build
Fighting Style
Dual Wielding is a bit ahead of any other style before level 5, but quickly falls behind Great Weapons from level 5 in raw damage. As a half-elf you could have put your Ability Score Increase and 15 in Str instead of Dex, making Great Weapons viable for you too.
With the Shield Master feat, even Dueling is ahead of Two-Weapon Fighting in DPR, while greatly improving your survivability, and usefulness for your party.
Feat Selection
Dual Wielder is weaker than an ASI, especially if you are building with Dex as your primary ability score. A +2 Dex to would give you the same average damage increase (1d6+4 = 1d8+3), the same AC increase, but would also increase your to-hit chance. Besides this, it improves both your Stealth and your Initiative.
Keeping up
Multiclassing can help, but not much.
Taking 1 level of Warlock for Hex is problematic with your Cha, but 2 levels of Ranger for Hunter's Mark would work. You could get a lot of mileage out of +1d6 on all your hits, but moving the spell to the next target is a bonus action, just like your off-hand attack. So the faster you kill the enemies, the less you can use the spell. At least with your Con save it is hard to end your concentration.
Taking levels in Rogue is a better idea, especially once you have the Riposte maneuver. Sneak Attack can trigger once per turn, so you can use it with your Riposte.
Note that everything listed here could be done with a Duelist, just better.