Lavos (Power of)
One interesting question is whether Lavos's power can be equaled to real life units of destructive force. A basic comparison of events allows this.
1.) In 65 million BC, Lavos impacted the surface of the earth at meteoric speed, creating a fireball that covered most of the continent and caused a global climactic change that lasted for millions of years. This explosion is similar to the K-T Meteor impact, which is estimated to have released energy equivalent to 100 trillion Tons of TNT. Additionally, this impact is theorized to have happened in 65 million BC in our own history by Luis Alvarez, lending credibility to this idea.
For comparison, the most powerful hydrogen bomb ever produced had a yield of 50 million Tons, and the total world nuclear arsenal has a combined yield of approximately 5 billion Tons. The explosion of Krakatoa, the most violent volcanic eruption in recorded history, released energy equivalent to 200 million Tons.
Lavos, a biological organism, survived this impact with no apparent injury.
2.) In 1999 AD, Lavos destroyed the surface of the earth in preparation for reproduction. It caused sufficient damage to destroy human civilization and significantly change the geography of the planet. This required several orders of magnitude more energy than was released in Lavos' impact, which was produced (presumably) by its magical power alone.
3.) Lavos also destroyed the Zeal Kingdom, the Black Omen and Magus's Castle (?) using magic attacks equivalent to many millions of Tons of TNT.
Together, these three observations can provide a rough estimate of Lavos's power: it is off the scale!
A New Attempt
Berf has gracious provided a new attempt at quantifying the power of Lavos, arriving at 3.10^28 W. See his work in this PDF.
From: Theory (People)