The Vulkantis have the ability to awake mountains from their slumber causing splash damage to be dwelt to all units next to it (Including your units) , with a modified Philosophy tech.
The Vulkantis can create Flame Archers which after attacking an enemy the enemy is inflicted with a burning affect (I imagine it would look the same as the flames when a city is being captured) that will do a small amount of damage for the next two turns, with a modified Archery tech.
With the power of a modified Free Spirit tech, the Vulkantis can build a Kiln which gives a city +1 stars per mountain it borders (one per city).
Vulkantis' super unit: The mindbender's tales of walking volcanoes are true, and they summoned one just for you (How nice of them), this walking volcano is ready to shoot lava up to two tiles away, do splash damage, AND inflict a burning effect on it's enemies.
Here we can see one of the super units of legend who just wanted 5 more minutes of sleep before being summoned.
When the Vengir was banished to their wasteland they found the Vulkantis and thought this was the wasteland they were being banished to, one record of a Vulkantisian's reaction to this was "C'mon man... that hurts".