It costs 5, thats why its a nice skill to use. Cast it on a few opponents in a battle. you will get healed whenever this hex ends. if an opponent gets killed whyle its on him, u get healed. if the hex ends ure healed, not sure if u get healed with remove hex.
Yes, remove hex WILL TRIGGER the healing power of this skill. One of the best heals for just 5 energy in my opinion if you do follow the curses line. I think curses is the best form of necromancer magic in this game.
Death Magic is very expensive and too conditional
Blood Magic loses oomph in higher levels.