This is a key concept in my "bulletproof angels" offense, to protect them from removal with Covenant of Eden, quasi-protect them from discard with Chamber of Angels, and protect them from capture with Fourth Living Creature. For added goodness, toss CoE into Book of the Covenant alongside I Am Justice to make a loss bite back at the opponent, or better still, with I Am Holy to make the opponent discard from hand, and keep discarding and recycling your numerous angels in hand.
It has its weak points - there is growing strengths in strategies other than discard/remove and capture these days and the Angel Wars Heroes only protect from a few of the more sneaky ninja blocks, and 4LC does not protect any of the Big Four - but I have fun playing with them. It's also fun to have Arianna and Kira in there so that angels can still go after any of the common restricting Lost Souls (female, NT, */4).