Whenever Grakk receives damage equal to more than 10% of his current HP in a single blow, he triggers an explosion, dealing 40 (+0) (+74) magic damage to enemies within 500 units (2-second cooldown). Grakk will also trigger an explosion 3 seconds after his death, dealing 160 (+0) (+299) (8% of his own maximum HP) magic damage to enemies within 500 units.
Grakk can hook enemy heroes from far distances, so try to hide in the brush when you are using Grakk to take key damage dealers out of the fight. Grakk also continues to pose a large threat after he dies. Finding a strategic death location at the right time will help your team immensely.
Grakk was known for his brutality. As the executioner, he shackled imprisoned souls, and tore open the offending souls with his teeth to torture them. He had to pay a steep price for this though. The price was that he could no longer digest any food other than souls. He needed to devour souls to satisfy his constant hunger.
To stave off hunger during times of peace, he had to ask for help from Zephys and Nakroth; the former harvested souls while the latter past judgment. All guilty souls became his food. After the war broke out, in return for Grakk's strength, Maloch promised Grakk that he could do whatever he wanted with the enemies he captured.
The never-ending feast turned Grakk into a war maniac. With every fresh soul consumed, his power grew. He turned all of the things he could not eat into the Fallen to capture more food for him.