Its actually based on Clairvoyance, the summoners ability from LoL. Area effect 2, Range 5: Affected units lose stealth, take fire dmg equal 50/65/80 % of this units dmg and become lluminated 4. Mind, everything in the area is Illuminated and destealthed, and only stuff that can take fire dmg take the dmg.
The destealth clause will only help if your opponent happens to have thrown the game by deploying a unit with Murk.
Depends, you can use it on a group of units to reduce their armor, and use it on stealthed units with incorporeal as well. But basically im looking for more abilities with destealth as detection is rather scarce compared to stealth units