I still can't get over him slaughtering the goblin children. That is not the action of a good or even neutral person.
He's a Druid. Circle of life.
No. Circle of life in nature means you kill in order to eat, or when you are threatened, not for sport.
Ahem... the goblin children are throwing Halsin/bear stones with the express purpose to cause him pain. The goblins mention loudly they plan on feeding him to the worgs. AND actually Halsin is not guaranteed to kill the goblin children. He kills the grown goblin near the cage but then the 2 children have a good chance of escaping (disengae without causing AoOs and then dash).
Personally I see no issue with Halsin reacting the way he does as the little sadists express delight at the suffering of other living beings.