This comp uses a Chosen Moonlight to make Diana a hyper carry at 4 stars with Moonlight. You really want to have a Spatula in the late game in order to hit 6 Assassin, but you can have 4 and replace some Assassins with strong late game units instead.
Just add in more Assassins to buff up Diana even further.
Additional comp tips
One of the win conditions of this comp is finding other 3 star units. Once you stabilize after finding Diana and Lissandra 3 star, you can look to try and 3 star units like Talon or Akali by slow rolling at level 8.