Finally I touched this character (even I do not like how this unit looks...). Basically the healing amount of the fire cupid is very high compared to other healers. I am developing him now (LV20) and he heals around 5k all team units. However one drawback is that it looks he need a lot of time to charge the blue energy. Sometimes this takes the first round. And imagine what happens if he gets a good shot. He does not reach this point. I am not sure at the moment if further development, perhaps boost attack to accumulate quicker the blue energy for first heal, would support a better use of this fire cupid character. The Korean MSL tier list rank him with a A+ by the way.