Post your interesting discoveries here! I'll be adding more as I continue to dig.
First off, Vampire Lord skill descriptions! Vampire Lord was the only one in strings_db--the descriptions/names for the playable characters seem to be in their ability files in the heroes directory.
Bat Swarm I/II: The Vampire Lord transforms into a swarm of bats, teleporting him to a new location and damaging everything in his path.
Bite I/II/III: Bites a target and drains 250/400/550 health. The Bite reduces target Armor by 200/400/600 and Run Speed by 20/40/60% for 5 seconds.
Mass Charm I/II/III: Stuns enemies around the Vampire Lord for 3/6/9 seconds. Demigods are stunned for half duration.
Mist I/II/III: Vampire Lord transforms into a deadly mist, dealing 50/75/100 damage every second to nearby enemies. While in this form he will lose 6.5% health per second and is unable to move or use other abilities.
Poisoned Blood I/II: On death, the Vampire Lord drops a poisoned potion, dealing 500/1000 damage to whoever consumes it.
Conversion I/II/III: Grants a 35/55/75% chance to convert a grunt into a Vampire with base attack. All other damage has a 5/10/15% chance to convert.
Coven I/II/III: Increases vampire minion damage by 20/40/60% and health by 10/20/30%. Increases max number of allowed vampires by 2/4/4.
Vampiric Aura: Grants 10% life steal to nearby allies for a short duration.
Attribute boosts: +120 Health +0.24 Health/second 6% Attack Speed Increase +60 Armor +200 Energy +2.4 Energy/second +8 Weapon Damage