This card always bothered me a little. The ability immortality says that the creature cannot be targeted. So, why should someone add a card that can target untargetable creatures. I know first it was created as a colorless Shard that should have an affinity to aether, therefore it was designed that way because aether and immortality go hand in hand but it makes no sense. Some might say: But this card only adds bonuses to the card. That's not true in some cases, for example if someone has any reflecting shields, suddenly your creatures turn against you and you cannot do anything against it because its ability makes it untargetable...
I recommend to delete this card or remake it, to make untargetable creatures untargetable again. Otherwise we have to add a card that makes untargetable cards truely untargetable. Or change the text of that ability to somewhat like "cannot be targeted by anything but aether cards" but i prefer to say goodbye to this card.