I have some success with Offensive Defensive hybrid. It works unless its under heavy attack(like by group of Orc warriors or dagger goblins and without support). Main issue is low Fatigue so reliance on Hornblowers/Sergants.
Preferable military backgrounds with high Fatigue/Hp/Md/MS – Hedge knights, Sellswords, Squires, Raiders. Swordmasters or Retired soldiers are to fragile and have to low fatigue although they have good MD and MS
Level Up stats
Melee skill- to hit
Melee defence – to be not hit
Fatigue – to wear heavy armour and actually do anything
HP – to not die easily
First build Defence tree.
Battle hardened/Colossus/9 Lives
Non shield user so no shield perks and low Initiative so no Dodge
Hold out – its essential as its plain free stats to Attack and Defence also morale. It working best with Inspiring Presence or Determined trait.
Then Offensive tree:
Sundering strikes/Executioner or Headhunter/AOE hit chance bonus
Why headhunter? If you use Zwaihander you want to use AoE attack and it looks like it benefit more than executioner(as enemy characters tend to die in 1-2 hit)
Berserker(for 2nd attack) and Full force(for more dmg).
Killing frenzy is optional but it really help.
2nd weapon is Dagger(0 fatigue cost)
Weak point is relative low Defence Skill compared to Nimble or shield one handers builds and low fatigue and fatigue regeneration rate as zero Utility perks.
This build cannot operate without Sergeants/Hornblowers.
It work rather well if supported. Biggest danger are orc warriors(as always), massed xbows and goblin daggers.