What's the deal with the Elemental Sword?

[Tuplis]

1) You can find them all by thoroughly exploring the underground caverns
2) For each altar the axe gets upgraded but this depends on the order in which you visit the altars.
I can't remember their exact stats but here's what I do remember:
-If you visit the ice altar first, your dwarven units will freeze opponents with their attacks
-If you visit the lightning altar first, the axe will grant +15% damage to lightning spells when fully upgraded
-Can't remember the last one but I'm pretty sure it grants something to dwarves only

Also, I think every version gives +5 attack to all units.