Lucent is a system which gives buffs to himes whose favorite weapon's type is matching your lucent weapon. It probably not really worth to fiddle with due to guardian weapons getting FLB. But I don't remember much on this, so yeah, lets wait for Geo's elaborations on the topic.

From limited himes ones i know worth of noting is ongoing Nyar and wind Osi. Also, water Agali's weapon bringing large assault/ large exceed to you.