@Radience WD affixes increase the damage of the weapon they are on. ED affixes increase the damage of the weapon if they are the same Element. MH Fire, OH Ice, Hat Ice with +5,000 Ice Damage. no damage increase for MH because it is Fire, but increased the damage of OH because they are both Ice. that +50% damage from a Myth Stone only increases the damage of the weapon it is on, just like the WD affixes. if you are using Prismatic (randomly change Element of attack), in the example I used above with Ice, when Prismatic changes the Element of the OH attack, it still benefits from the +5,000 Ice, even if it gets changed to Fire. but the MH Fire, if it gets changed to Ice, it doesn't get the benefit of the +5,000 Ice, as the base Element of the MH is Fire.
@Marcosbankings those Quests that pop up when you start to play DQ were only around for a little while, and are no longer available. Dev's have said they probably wont bring them back. @ZOMBOY is right, the only real Quests are in the Codex. the most noticeable ones are the Feats that you complete for Hero Points and rewards of different kinds. other Quests are up to you. get all Legend/Eternal items, get a Rogue/Wizard/Warrior to Rank 1 in Eternal League in Battle Arena, get to Floor 3,500, get to the top of one of the Leader Boards...pick a goal/quest and go for it.