Originated from the immortal snake. As one of the offsprings of Typhon and Echidna, it was used by Hera to threaten Hercules. It possessed deadly venom and had 9 heads. One of the head possessed the ability of immortality. Hmm, I can see only 7 heads. Well, it doesn't have to match the legend exactly.
AP +800, skill activation chance +1% to all Underworld cards