For the protagonist return to the snow dungeon artifact room. walk past it and you will find a tile to step on. Next leave the dungeon and in the map tile you exit into you will find two other buildings to enter. Enter one and finish the mini dungeon inside.
For Garet return to the snow village enter the buildings untill yyou find the side quest.
For Lex return to the arena in lemuria.
For Slib find the portal on the left side of the long bridge.