That was hardly a merit of the barbarians:PThe three legions were under the command of Publio Quintilio Varo, which actually wasn't a military commander, but an uptight noble that wanted to play general.
The area was relatively pacified, and germanic tribes were on their way to be slowly integrated into roman civilization, but when Varo arrived from Rome and replaced the officer in charge, he started to treat the germans as slaves, and raised the local taxes to an impossible rate, thus angering even those that were starting to accept roman influence.
He was a noob on all fronts, and the reason he lost three entire legions is that he made them march along a narrow road in the middle of a thick forest that was well known to be swarming with germanic tribes. He was on his way to quell a small rebellion nearby; there were plenty of voices and reports saying that the rebellion was fake and an ambush was very possible, but Varo simply ignored them, wanting his own personal day of glory in battle (hidden behing hundreds of legionaries, of course).
The cosmic noob procured such a devastating defeat to Rome that its military machine didn't recover for many years, leaving the germans free space to expand and consolidate. After that, the reconquest of the area was impossible.
' Wrote:You state that an extroadinary military can not be beaten by a minor power using guerilla tactics? Vietnam War anyone? I disagree on that point, a war can be won in that manner, however I do find it hard to believe they caused the amount of devastation they did via guerilla tactics.
In order for a minor power to win in an asymmetrical war, the major power has to be reluctant or unable to resort to unscrupulous tactics such as decimation, internment, or in this case declaring war on Kusari in order to take out the GMG's supply lines.