Ok heres the senario, You have 15+ Necron warriors plus Nemesor Z.
You have Obyron on the board, and Z is charged.
Now the way I read the rules. Obyron piles in. Now in your next turn Obyron can use is cloak to port the entire unit out of combat and to safety.
For this to work, The unit must not be destoyed or be broken and swept in that one round of combat. The second part is important as if you are likely to be swept away, then you have lost two characters in one combat.
So is Obyron + Z a nice combo or a nasty liability.
It probably depends on the CC unit, but I'd be interested in knowing what to look out for.