Whenever your unit that has the Protector keyword is ready and your opponent applies an ability at the same quest, that ability creates one less level token.
"So cold was Harkin Iceale that 'e drank a keg o' ale. He be so snockered 'e did'na see big, bloody Yeldema dead ahead. That Dragon swallowed 'im whole, she did. Ne'er drink ale to keep warm, I say. Drink to get drunk!" --Thubr Axebringer, Dwarven Ambassador