How do you help the sewer person in Stick RPG 2?

you have to go to the fourth land at night and by the poolish place are a bunch of sewer people. Fight them and win and you get the key to the sewer.

Hope i helped :)

Hugod:Go to the 4 world at night, Then click the Sewer King,U Win 2 Get Key(Warning, It Is A Combat Zone)(I Beat It)