The Celts and demi-Celts of the Alps use the Gaedotos as a form of phalanx, adopted in their style and gear mainly from the Etruscans.
The alpine tribes experienced a great deal of influence from the Hellenes and Italians. The Appea Gaedotos (Ap-ee-ah Guy-doo-tos; "Spear Carriers") use a type of spear wall, and carry a very bizarre shield, as well as a battle axe for close combat fighting. They are solid soldiers, and should be able to stand rather well in combat, and a phalanx is always good when combatting mounted enemies, as well as defending against light infantry. In close combat, their battle axes can crush through armor, making them very capable, and they wear linen armor of Etruscan design, so they are readily able to defend themselves.
Historically, the Alps were home to many tribes, both Celtic and non-Celtic. Both, however, used a share of one another's weapons, as well as weapons and tactics from Greece and the Italian peninsula. These soldiers would be, in essence, a type of imitation hoplite, with influences from the alpine tribes. Due to their climate, they would've been very hardy soldiers; coupled with their culture, which glorified combat to a great extent, these would have been truly fearsome warriors.
The Appea Gaedotos are highly capable spearmen and line infantry, boasting a solid and impregnable formation comparable to a Hoplitai (Greek Classical Hoplites), ensuring they can hold out against heavy odds with their flanks secure, especially with guard mode on. They also carry armor-piercing axes, making them deadly against heavy infantry and cavalry attacking and also making them good for a flank attack.
These men are especially useful for the barbarian factions as well-armored line infantry, effective against the Romani faction with their focus on heavy infantry, with the Gaedotos holding the line while hacking the attacking legionaries with their axes.