What happened to my sword?

Edit: Never mind, found it. Was looking for wrong thing in search.

A magic weapon from a Rt/X or X/Rt.

Yeah, it's just the Weapon Spell Skin. Happens to all weapons when said spell is cast on you. It turns back when the spell ends ^^

Yes, Aeson is a ritualist, ritualists have special skills which temporary 'modify' a weapon, giving it bonuses like extra life, or more damage, etc. Your weapon is still the same, although the skin temporary changes, and you will get more out of your weapon. What it does, you can read in the top-left part of the screen, where your skills are placed.