At the end of the Hearts of Stone quest “Whatsoever A Man Soweth”, should Geralt allow Master Mirror to take Olgierd von Everec’s soul (whether Geralt met with Shakeslock or not), he will then allow him to ask for a reward.
This video shows what happens if you let Master Mirror take Olgierd von Everec’s soul at the end of “Whatsoever A Man Soweth”. Olgierd meets a gruesome end and Gaunter O’Dimm will offer you a reward.
Viper School Witcher Gear is an addition that crops up in certain places in the game – the standard weapons at the very beginning of the base game, and the armour and venomous weapons at specific points in Hearts of Stone.
Gaunter’s riddle challenge is strictly against the clock and there are various distractions put there along the way to slow you down, including a variety of spectre monsters.
You can let Olgierd’s soul go for a reward, but I want the Viper Venomous Silver Sword, which is only available if you challenge Gaunter O’Dimm.
You need to visit Shani one more time – BEFORE going to the Temple of Lilvani to meet Olgierd and Master Mirror – in order to play her at Gwent.
After a short fight with some Witcher Hunters, Geralt talks to Professor Shakeslock about Gaunter O’Dimm.
A memorable scene with Gaunter O’Dimm at The Alchemy Inn in Oxenfurt, then a visit to Shani to try to find out more about what Geralt’s up against.