Hendak is a proud warrior from the North untill his capture by slavers. He has been imprisoned longer than any of the other men and survived, though only barely while trying to aid the other slaves in pit-battles for the amusement of noblemen as best he could. He is found among the slave cells inside the Copper Coronet, owned by Lehtinan (whom he refer to as a fiend) where he request help from the player's party to free the slaves in the quest: Free Hendak and the Slaves.
In the south-eastern corner of the Copper Coronet you will find the Beastmaster whom you must kill and who drops the key that unlocks the slave cell doors. Freeing Hendak will cause him and the other gladiators to sweap through the Inn, attacking the guards and eventually Hendak will confront and kill Lehtinan, taking over the Copper Coronet. 
After the take over, he will request further aid in ridding the city of slavers.