Summary: Remember the old Aegis CItadel combo with Edin? Here is a bit better combo than that.
270. Moggy Howdah
Edin, the Persecuted
How does this Unit work?
Simple in your first turn, summon a green cubic on a wood field. Next turn summon Moggy Howdah off the green cubic, then Edin facing the same direction as Moggy. Now both Edin and Moggy has the invisibility i.e. no physical, magic or spell attack can damage neither creatures. And all the subsequent allied creatures gain invisibility as long as they are facing the same direction as Moggy.
Clearly there are ways to counter this as Set.3 introduction suppose to allow us counter anything in the game. Some of counter include Fog, Fissure, General Lag etc.
The key thing about this combo in comparison to the Aegis + Edin is that there is no Summoning Lock i.e. you can complete this combo as early as your second turn!!