In the beginning, Tyr had planned to stay out of it, and managed to do so for a while. The Northern tribes, suffering too many years of meager harvests and unusually cold temperatures, had no choice but to migrate or watch each other die of starvation. This part he understood. When they began to enter lands belonging to others, fighting their way through, that was when the problem came in. Yes, they needed food. But the land belonged to someone else, and it was only fair the Romans defend what they thought was theirs.
Then came the ambush under a guise of truce and words of treaty.
That was something that did not sit well with Tyr. After that, when his people cried out for aid, Tiwaz, as he was known to these tribes, was there, sword in hand. Some battles they won, some they lost. And he wasn't always called. There were times when the people of the tribes of the Cimbri and Teutones knew they had it well in hand. Tyr could appreciate the desire to do it on their own, even if it was a bit boastful. Perhaps that's why he didn't hear about this latest fight until it was too late. By the time he got to the hill by Aquae Sextiae, he knew there was no salvaging the battle. For the men that had raised arms, there was an expectation that this sort of thing could happen. But the pleas for strength and the screams from the woman and the cries from the children... Children, for Odin's sake! One look told him all; the women were killing their children and then themselves, rather than risk being thrown into slavery by the Romans. Or worse.
What kind of barbarians were these that small children, even infants, must sacrifice their lives rather than be captured?
Already, he knew there was nothing he could do for them, other than stand with them and hope his sword could cut down a few of the Romans before they could do this to someone else.