The axes? I can't tell you specifically why. I imagine it's because they serve as both a survival tool and a formidable weapon. I also suspect that the axe is overstated a bit. The spear would have likely been the weapon of choice in formations as it is in pretty much any culture. I mean, what weapon do you think of when you think of the Japanese? It's the Katana. Right? But, the truth is, in formation, the Japanese relied on spears more than the Katana. The spear is cheap to make and requires almost no training to use. So, you can quickly create an army of spearmen. But it would be difficult to create an army of seasoned axe wielding berserkers. So, like the Katana. I think the Axe is largely romanticized. The spear is also the favored weapon of Odin. So, it's not like the spear wasn't considered worthy. As for the Slavs. I have no idea about the Slavs. You should ask a Slav guy. I'm not a Slav guy. I won't pretend knowledge about the Slavs.