I'm looking at
RO DataZone - Attacks now, just to verify how it all works:
- All cards, regardless of which weapon or hand they are in, apply to the right-hand attack value only (so if you have one weapon that's DDT, and the other is HHSS, then your right-hand damage will be factored as THHSS, and your left-hand damage will be without card bonuses).
- "Note: In the case of a Dual Wielding Assassin, steps 1-28 should be completed separately for each weapon."
Okay, so it is done separately, so if one weapon is Earth and another is Wind, each hit will factor in its respective element, and not be influenced by the other. However, if either or both weapons are carded, then all cards will apply
only to the right-hand attack. So whatever weapon you want your cards to apply to, put in your right hand. All your other daggers will switch in and out of your left.