Harold Mews apparently offers a reward to whoever manages to find irrefutable proof of the existance of cryptids. He first appears when he rescues you after Gretchen Grimlock burns your kite while you were kitesurfing, stranding you out at sea. He then allows you to use his helicopter to find proof of cryptids. He also helps you in confirming the authenticity of the evidence you find. After confirming the existence of the Chupacabra, the Jersey Devil and Nessie, he alerts you to a Bigfoot sighting in the Pacific Northwest. You then track the sasquatch down to a cave, after which Gretchen Grimlock arrives to steal Bigfoot. After freeing Bigfoot, Mews tells you that he wished to buy up the land around Bigfoot's cave to create a sanctuary but that he lacked the funds needed. You then turn down the previously promised reward in order to help Bigfoot. He is impressed with your selflessness and gives you the Island Medallion.
Trivia
His name is probably derived from the phrase "Herald News".