I finished the side quest, "Bringing the Light, Bringing Noise". When I battled solo spamming meteor, a creature "Phantom Devotee" regens more health after one round of any attacks. There are also some few creatures that are regening health after one round.
Also, there was also a creature and a player issue. When a creature or players in pvp were defeated in the battle, they can still get pips and cast spells or the battle is not finished unless you defeat defeated players that had pips.