Highlander Cicern Armies & culture are Incorrect

[SaturationPlotting]

With Respect... I disagree with "Total War" devs take on the culture and Armies of Highland Scotland

It is known that the "Gaelic" culture was migrating into Alba or Caledonia... but the main immigration was more peaceful movement of people rather than conquering.
The most "Scotti" of regions was on the western coastline with Clan Campbell (Argylle or anciently known as Dalriada) and lowland regions around modern Glasgow (anciently known as Strythclyde).

The (old Picti) Highland Scots still retained their old language and identity. They very slowly changed (last) after lowlanders were speaking Scotti rather than ancient Picti.
The idea that "they were the First to Fall" seems ridiculous (retreat to hills and swamps)...
...since they were one of the most resilient and protected from invasions (from Romans to Vikings)

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Highland Picti (or Scot) warfare and weaponry was different than many other nation tribes of "Britannia".

I only see historical articles referring to Crossbows in statues around ancient Alba.
I don't know whether they were used for war as much as you make them out to be.

Instead... the "Highlanders" were very famous in their use of "long PIKE" units.
In many of their battles with Rome, England, and others; it is well documented that Highlanders used PIKE in a "wedge formation".

An example of this is the latter Battle of Stirling Bridge (1297)...
...where Andrew Moray (clan Fortrui ) used traditional PIKES in wedge formations to charge through to the bridge landing and prevent reinforcements.

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One of the most common things about Highlander warfare was their "Highlander CHARGE".

The Highland Charge was a battle tactic going back to ancient Picti warfare to the near modern day.

The Charge was immensely successful "because" it employed WEDGE formations of PIKES, Spearmen (w/shields), and Swordsmen that would come from both Front and Flanks.

The Highland Charge was successful most often when they could employ a level of Ambush plus be able to BREAK THROUGH a line of infantry into their rear and envelope them.

[making a game reliant on missile units... such as your Crossbowmen... really does NOT represent TRUE Highlander warfare]

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Some historians FALSELY argue that the Highlander PIKE or longspear (w/shield) formations only started with William Wallace (1250 ad).

I believe that to be very inaccurate. Highland warfare was very long and deep. They (like other "wide tribes") taught their warfare from father to son for eons.

The English that fought Robert the Bruce at the Battle of Bannockburn (1314 ad) that the Scots had few archers, slingers, and crossbowmen...
INSTEAD the Scot warfare was swordsmen, PIKES, and javelins... !

The English would later go on to be wary of Scottish SCHILTRONS of "pike divisions".

[it was very documented that Scot Schiltrons ATE enemy formations easily]
https://en.wikipedia.org/wiki/Schiltron