Vanilla Barbarian with Polearm Master and GWM starts at net 10 damage, and averages about 30 net damage per round
I think it is a trap to worry too much about bludgeoning. First, you'll fight not only undead, there will belots of other monsters -- without disclosing anything about the campaign, for Dracula-style gothic horror think wolves, bats, lunatics, were-creatures, gypsies, scarecrows and so forth. Second, among undead only skeletons are vulnerable to blunt weapons, and at a mere 13 hp they can go down in one hit either way. You will get much more mileage from just optimizing for gross damage output.
Assumptions and build
Race: Variant Human, pick Polearm Master
Ability Scores: (assuming the standard roster)
15 Strength, +1 from Variant Human for 16 (+3)
Rest however you prefer, probably set to get +2 on Dex and Con.
Weapon: Glaive or Halberd 1d10 slashing (and 1d4 bludgeoning with butt)
Rage: We assume 5 encounters per day1; Rage will on average only add a fraction of the full damage per attack equal to the number of times we can rage out of five, until we get to 5 rages per day on level 12.
Your raw average damage per round will consist of Attack action plus Bonus Action polearm butt, with Great Weapon Master (GWM) once you get it.
Your expected damage per round will consist of that times your to hit chance. Because to hit is heavily influenced by GWM we calculate it for each level. It assumes AC on average equal to what DMG p. 274 recommends for monster AC by CR. You always attack with Reckless Attack to offset the to hit downside from Great Weapon Master. You deal more damage this way than by the higher to hit chance. (Pick Bear Totem to soak up some damage this will cause you.)
Level |
Relevant Feature |
Rage Dmg |
Raw Dmg |
To hit (%) |
Dmg/Round |
1 |
Rage, Polearm Master |
0.8 |
16 |
+5 (65%) |
10 |
2 |
Reckless Attack |
0.8 |
16 |
+5 Adv (87.75%) |
14 |
3 |
Path Totem |
1.2 |
16.8 |
+5 Adv (87.75%) |
15 |
4 |
Great Weapon Master |
1.2 |
36.8 |
+5 -5 Adv (57.75%) |
21 |
5 |
Extra Attack |
1.2 |
56.8 |
+6 -5 Adv (57.75%) |
33 |
6 |
|
1.6 |
58 |
+6 -5 Adv (57.75%) |
33 |
7 |
|
1.6 |
58 |
+6 -5 Adv (57.75%) |
33 |
8 |
ASI Str +2 |
1.6 |
61 |
+7 -5 Adv (57.75%) |
35 |
9 |
|
2.4 |
63.7 |
+8 -5 Adv (64%) |
41 |
10 |
|
2.4 |
63.7 |
+8 -5 Adv (57.75%) |
37 |
11 |
|
2.4 |
63.7 |
+8 -5 Adv (57.75%) |
37 |
12 |
ASI Str +2 |
3 |
68.5 |
+9 -5 Adv (64%) |
44 |
Considerations for build choices
The unexpected choice of this build is to defer maximizing your Strength until level 8. Normally, +1 to hit and damage is the best you can do (and it has other benefits like for athletics, grappling, carrying stuff; there are few saves for it), but it is not better than getting the combo of Polearm Master, Rage and GWM as fast as you can.
As shown in this answer, greatsword (or maul, if you want bludgeoning damage) is a great weapon choice for consistent damage. The increase from 1d10 to 2d6 is worth about 1.5 points, later 3 per round with Extra Attack. Polearm Master however gives you an extra attack worth 6 points intially and later with rage and GWM over 16 points, outperforming this by far. The bonus attack also deals bludgeoning against skeletons, if you care about that.
We are not using Path of Berserker for Frenzy, as you have good use for your bonus action with Polearm Master and it is not possible to keep Frenzy up during each fight. One use you can sleep off, after that it goes downhill. For one fight with a maul, this would be worth 2d6 instead of 1d4, or 5.5 more damage, but even that and better base damage would not compensate for the remaining four fights without bonus attacks.
The early extra attack from Polearm master with variant human also outperforms the expected small contribution from half-orc's Savage Attacker (about 0.35 points with a maul) and even from playing a hobgoblin (worth over 7 points in the surprise round, but nothing afterwards, and a normal fight takes 3-4 rounds). I think it is also better than two-weapon fighting, because you get to apply GWM to all your attacks.
Beyond Single Class and PHB
This assumes no multiclassing. You get more out of it taking a couple levels in fighter for action surge. If you took the last four levels in fighter, using raw numbers it would cost you about 3-5 points a round in missed rage damage improvements and brutal criticals, but you could pick Great Weapon Fighting style at 9 to get 2.2 points back, action surge at 10 to double your Attack action once per fight for another near 50 points, martial archetype at 11 to take Battlemaster and get superiority dice that help further with hitting or extra damage, an still pick ASI at 12. Overall you'd come out clearly ahead by over a dozen points per round.
I also like the idea of Someone_Evil to take Path of the Zealot over Totem Warrior for access to radiant damage, which really helps against Zombies. If you do not care for your own hp, you could add that for an extra 3.5+(0 to 6) points of radiant damage a turn.
1 This is based on the recommended XP per day from DMG p. 84 and encounter XP thresholds from DMG p. 82. It the average for Medium to Deadly encounters, as in my experience easy encounters are rarely used. Including Easy, the average would be 7 per day, lowering rage damage a bit more, but it would not have a material influence.