At the side of the Church in Hugel, behind a tree and a bridge.
-- 10 000 000 zeny and the following: --
Sage Worm Card x 1
Argiope Card x 1
Dryad Card x 1
Wooden Golem Card x 1
Bongun Card x 1
Pirate Skeleton Card x 1
Marduk Card x 1
Hode Card x 1
Elder Card x 1
Nightmare Terror Card x 1
Rune of Darkness x 1000
Bloody Rune x 1000
Valkyrie Helm 
|You must carry at least 10,000,000 zeny in order for him to tell you about the quest and the items required.|
Talk to him a few times, he should mention the Valkyrie Helm and ingredients.
After you gave him the items and zeny, talk to him again and again until you get what you want.
There is a 1/10 chance to get pass the "....Let's wait a little longer." dialog. Then there is another 1/10 chance to get pass the "The materials are still being fused." dialog. Don't worry, just keep talking to him.
Airship to Yuno, Hugel, Einbroch, Rachel & Lighthalzen