Berserk (or Berserker)! They were the warriors in old
Scandinavian literature who distinguished themselves in battle by their
'berserk-fury' during which they roared madly, bit their shields and
became invulnerable. During these bouts of fury they were stronger than
bears or bulls. They would kill many men but were themselves unharmed by
fire or iron and they would be impervious to pain. In one legend a
berserk could allegedly blunt an opponent's sword's edge just by looking
at it.
In literature berserks are stereotyped in two ways. They are the elite
troops, often in groups of twelve, who serve famous kings. On the other
hand they are wandering troublemakers, alone or in twos and threes, who
challenge farmers of their own peoples to single combat duels to demand
wives and daughters, and they are then only beaten by a hero.
The name berserk comes from 'ber' = bear and 'serkr' = shirt or skin.
(Do NOT use the name 'Marauder'. That word is probably of French
descent!) A bearskin was all they wore in battle. They wore no armour
but they used conventional weapons like swords and shields. One of the
famous Isle of Lewis chessmen is shown biting his shield.
The berserk rage is an example of 'wod-ness' or furious madness, and is
obviously the source of the modern phrase 'to go berserk'. It comes from
their dedication to their god Woden (wod-en or furious), known as Odin
in Scandinavia, and the trance-like states they achieved.
Woden/Odin is part of the family of heathen gods and goddesses which
include Thor and Freya, and so Polytheism must be an advance
prerequisite for this unit. It can lapse when that civ discovers
monotheism or is subject to Christianity in some way.
Berserks should have high attack and defence and high hit points, but
they should be expensive to build, and especially be very expensive to
maintain since they are a liability to their own forces and populace
unless they have a battle to go to.