Apparently you get the quest when your arkadions reach level 70. At least that’s what happen to me. I’ve completed all the quests and was still missing the Barricadus recipe. When some of my arkadions hit 70 two new quests appeared in Reijin. One was to fight the guy on level 2 of Deucalion Tower. That’s where I’ve finally got the recipe.
Thank you so much for this information. 
who were the arcadions please, i already have 10 lvl 99 and still no new quest… :’(
Anubis, Penguini, Coldheart - these are the level 70 arks I have. But I don’t think that matters really. Perhaps you’ve missed some prior quests? I would check all the towns again just in case. I also passed all the rank tests, maybe that’s important. Still haven’t finished the tournament though, last battle.
Have you defeated the guy who was looking for ancient artefacts in the tower yet? Because I’m pretty sure you get the recipe from him once you do
That’s just it, they can’t even meet that guy because the quest is not available yet.
Try beating the storyline first.
If you did, I’m honestly stumped.
If that helps, the questline starts in Maldan. Until recently I didn’t get that Maldan is not a guy but a town (outside of the storyline), so I was kinda lost too despite reading the hints in the forum. 
Maldan -> Arborus -> Lassandal -> Kallaku -> Reijin (if my memory serves correctly).
Why don’t I see Maldan anywhere?
From Geat, go 1 South, 1 west, 1 South, 4 East, 1 Southwest and 2 South.
Here is a map with Maldan on it