the current parasite is not very efficient because players can spent your mana very fast, problem that most skills that drain mana does not, so to solve the problem, how about changing the parasite to new skill that provides mana for BM during 3 turn? working like a reverse frostbite. the name of skill can be "blood recharge"
i am not a epic duel developer and the current parasite drain the enemy mana, so not is totaly reverse frostbite, i know that the BM will be the only class that not drain the enemy mana, but to balance this fact, the new skill can be little OP.
What do you mean you're not a developer? You don't have to be a Dev to suggest skills in detail (Take Nexus's post in the Balance section for example).
All I'm asking for is some more info about this skill, since I don't really know what you're trying to suggest.
Example: Energy Parasite gives 5 energy per turn at level 1. Increases to 20 Energy per turn at level 10. Usable with a Staff or Sword. No stat requirements.