The goblin hunting and goblin's demon leader

It has been 8 months and 3 days since James started his work. Today, he was at cave and reading something and training. Jack come and asked: Any new work, Lord dark nightmare? James said: There aren't any crimes happening, but I have discovered something abnormal. Jack asked: What? James answered: There were reports that on this island few people went missing and found dead. This still remains a mystery. Jack asked: Who do you think might have done this? James answered: I send some cameras around the island and they showed this. James showed the film to Jack, Jack said shockingly: Goblins? James said: Yes. They are creating big troubles in there, so I want to go there and kill them. Jack said: I want to come too. James said: You need to get trained before that. Don't worry about other victims. The military have destroyed bridges, so a civilian can't go there. Jack accepted and they started training. After 3 days, Jack was ready. They put on their clothes and roded the dark wing and went toward the island. They landed on the island and started searching the area. They walked only for 2 minutes, when they heard voices. Goblins came out and attacked them. They started fighting back. James used a sword to cut the goblins neck and Jack used an axe. After cutting some goblins, lots of them came out. James took out something and throw it toward them. It generated a strong light. James knowed goblins couldn't tolerate light and that was the reason they usually stayed in dark places until sun sets. They cut the necks of all goblins. When they were finished they went around to look to see if there were any other goblins. While they were searching, something came out and landed before them. That creature said: I thought I heard some voices, it seems whoever you are you were able to kill my goblins. Jack asked: Lord dark nightmare, do you know this creature? James said: Yes, his name is Onilion, he is a demon beast that was send by devil. This beast has the ability to walk on two foots and has strong claws and darkness power. Onilion said: Oh, you know me. I am honoured. James said: I think we talked long enough, let's fight. They all got ready to fight. Jack attacked the beast. The beast stopped his attack with his hand. Then the beast throw a punch. Jack was able to dodge it. Then the beast attack fastly with it's claws. Jack was able to dodge them. Then the beast started using his darkness power. An area of dark energy surronded it. Then Jack activated his power scared arts. The beast shot a dark ball and Jack throw a holy ball. The balls hit each other and caused an explosion. Then beast started running on it's hands and feets. He attacked with it's claws. Jack dodged them and then he fillied his right hand with power of light and throw it. It hit the beast and the beast was hurt. Then the beast fell to it's knees and said: Hahaha, I would have...never thought...someone could...match with me...in fight...and defeat me. Then it said: Goodbye. Then the beast died. With this the mission was completed. They went back to their cave. Jack said: We did great, Lord dark nightmare. James said: Yes, we did. Also from now on don't call me with lord and call me dark nightmare-sama. This has the same meaning, got it, White-kun? Jack: Yes, dark nightmare-sama.