We currently have four factions for Total War Rome 2 confirmed – Rome, Macedon, Carthage and the Iceni. Now, the Celtic Arverni have joined the roster.
There is a ton of information on the official Total War Wiki, but here is an excerpt;
“Heavily dependent on infantry, the Arverni make great use of javelins and the devastating impact of the charge, led by elite warriors such as Spear Nobles and Oathsworn…. Noted craftsmen, the Arverni enjoy improved income from their artisans, as well as profiting from the Gauls’ expertise with gold-working. In battle, their cavalry benefit from natural Gallic horsemanship, while the charisma and fighting prowess of their kings and chieftains make them formidable warriors, and earns them diplomatic respect amongst other barbarian tribes.”
So, it is looking like you will get a nice bonus for using infantry units, and to a lesser degree, cavalry as well. It seems that their trade will mostly be to do with smithing and the sale of weapons and gold, as well. We have covered this topic in a lot of detail on the main channel, so watch the video for the full info.