Holy healing spell to recover the target's HP. The minimumHP recovered by this spell is 30% of the caster's M.Atk.
Shop for soul stones that boost your Int and socket these in a 2H staff. Smart rings boost your Int as well. Int gives you a MaxMP boost but also a magic attack (M.Atk) boost. Higher M.Atk yields higher HP recovery per heal for any team mates you are healing.
The net effect is that your limited supply of mana (MP) lasts much longer.
If you decide to have an int build for your character, use the skill Energy Beat with your staff for maximum effectiveness, NOT a mace which is based on str.