In the Animation, during the M’arrillian Invasion, in order to maximize the effects of their plan of flooding all of Perim, the M’arrillians had to reshape part of the land by building dams in strategic Locations. And because the M’arrillians aren’t much of manual labour they have to brainwash other Creatures to work for them.
After the events of Newbie, Kaz stubbornly wanted a scan of Milla’iin and convinced H’earring to keep an eye out for him. When they went to check a hint H’earring got, they came across the M’arrillian leading the construction of a canal towards the Marsh of Murk. When Kaz tried to get his scan, the Milla’iin sensed their presence and, almost instinctively, attacked with his brainwashing attack. While Kaz managed to escape, H’earring got hit, coming into play, the Tainted.
Surrendered to the power of the M’arrillians, H’earring’s appearance changed significantly. With wider eyes, opened enough to allow the back nerves to be seen, and an overall malign expression, he then becomes a loyal Minion, much more powerful but also very coward, fact that could be seen when he faked getting back to normal, exploring Kaz’s feeling to rescue him after being kicked out of a cliff.
Becoming a M’arrillian Minion also changed his innate ability, allowing him to force his opponents to attack in a way different than intended. A very handy ability that may also be a double-edged sword, if this little mental trick ends up forcing the adversary to attack in an even stronger way than they originally planned.
However, when commanded by a M’arrillian Chieftain, Creatures capable of brainwashing other Creatures, H’earring’s abilities change once again to better suit the Captain, allowing, at expense of a Mugician of every Creature remaining in his squad, teleport everyone to a different Location, chosen from three as his master sees fit.