Gaunter O'Dimm

Gaunter O'Dimm sometimes called Master Mirror or Man of Glass, presents himself as a former merchant of mirrors, now a mangy vagrant. However, as one might suspect, he is a much more powerful individual, celebrating pacts with men and women in exchange for their souls and being able to control time with the clap of his hands. His identity, origins and agenda remain clouded in mistery, but even some suspect he is Evil Incarnate the roots of all evil.

The Witcher 3: Wild Hunt
During quest Lilac and Gooseberries, you find him in White Orchard's Inn, he knows about Geralt of Rivia and Yennefer of Vengerberg from Mister Dandelion's ballads and advises you to go to Nilfgaardian garrison near by. Then, he suddenly dissappears.

Later during the Epilogue in White Orchard, in one of sidequests, one of the five dwarves from the Isle of Mists mention O'Dimm as "Mr. Mirrory", the recipient of chalice they had lifted from former Lord Dagborg.

Hearts of Stone Expansion
He is a major character and mysterious contractor that hires Geralt in the Heart of Stone expansion for The Witcher 3: Wild Hunt. He also can steal souls.

Gaunter O'Dimm's true identity remains a mystery throughout most of the game, with Geralt becoming increasingly suspicious of the true nature of this "man" - who apparently shows a godlike amount of power by stealing souls, granting wishes, controlling time itself. However, O'Dimm refuses to reveal his true name to Geralt, warning that those who learned it suffered a terrible fate.



The witcher, thanks to Shani's help, eventually finds Professor Shakeslock in Oxenfurt .This man, forced to be a hermit out of fear in his own house, reveals that the Man of Mirror is in truth "Evil Incarnate", an entity whose presence could be recorded throughout millenia, in different cultures, and appears to relish meddling in human affairs, collecting souls and causing misfortune.

Geralt may learn how to circumvent the pact made with Gaunter O'Dimm, challenging him to a bet, playing for his and Olgierd's souls. If he succeeds, O'Dimm is banished and the pact dissolved. On the other hand, if nothing is done to prevent the Man of Mirror to take his due payment from Olgierd he departs with the skull of his victim, quite satisfied.

Trivia
Hombre de cristal
 * Randall Flagg- character from novels writed by Stephen King has lot of names one of them is Walter o'Dim. Gaunter O'Dimm also shares simmilarities with Leland Gaunt from "Needful Things" - an evil entity who grants human wishes in exchange for evil deeds.
 * Pact with Olgierd is a reference to Mr Twardowski, a story taken from polish folklore.