Keep Location: Bog of Vipers.
Each time a hero attempts to place an order, he must roll a power die. On a blank, the order is discarded without effect. On any other result, the order is placed as usual.
Mistress of Serpents has the attributes and abilities of a Diamond Master Naga, in addition to any Avatar Upgrades you've purchased (including upgrades that affect Nagas).
Monster: 10, max 4
Event: 15, max 3
Trap: 10, max 4