The Blood Dragon Empire Series by Andy Remic

Five noble war heroes of Vagandrak get drunk one night and sign a contract – to journey to the Karamakkos in search of the Five Havens where, it is written, there is untold, abandoned wealth and, more importantly, the three Dragon Heads – jewels claimed to give unspeakable power and everlasting life to those who wield them.But the Dragon Heads aren’t what they think, and the world has not encountered their like in generations!Think Smaug was fierce? You ain’t seen nothing!

Part two of the high-octane fantasy series, from the natural successor to David Gemmell. A group of heroes makes dangerous bargains in order to overthrow the dragonlords and their Dragon Engines.