Odulir had no other choice but to explain that he got forced by the Dark Elf to create a magic gate according to the artifact sketch. After all, he didn't want to languish in the dark and damp prison of Redredane. So, it wasn't a bad thing for him.
As for why he was able to come to Redredane, he didn't understand the story himself. What he remembered was when the Magical World was in an earthquake, he was busy returning to the dwarf castle inside the volcano cave. He didn't want to part with all the things he had made and collected. But on the way, he found a translucent blue and white gate. As the castle floor was starting to crumble, he gritted his teeth and entered the gate. And so he arrived at Redredane, the sanctum of the dead.
Ji-woo actually wanted to listen and inquire further. However, he preferred to get out of the dungeon as quickly as possible. For the valuable magic items there, it wouldn't even compare to Silverstorm Odulir.