Just a little something that may be cool for an in game event.

Basically, we have our little moon lunatic here, and our praise the sun . After a bit of thinking, their relationship is probably the most noticed out of all of the events and lore. Sun versus Moon, a classic theme, right? Well; why not make this an actual in game event much like the Frelijord event between Lissandra, Ashe, and Sejuani?

Basically at a certain level, a little box will appear in the corner labeled "Lunari vs Solari" or maybe just "Sun versus Moon", something along those lines. And much like most of the events like this, whoever succeeds in killing the other will gain a small accessory or cosmetic.

If wins: Diana permanently has a snow-white aura surrounding her, like how she did in her login theme. If wins: Leona permanently has a blazing aura surrounding her, like the flames of the sun.

Of course, there's probably tons of other ideas we can use in this scenario, but I just thought an event between these two is practically mandatory with all the lore between them.