Talk to the judge, sends you to Joan in IT, she in return sends you to Sea of Spores to kill some spiders, usally 3 only required. Return to Joan and then return to hardins, she gives you a list of items to take to the blacksmith in Giran. Just buy them, make a blacksmith frame also and chat to the blacksmith, he makes the item which you take to the black judge at hardins.
Extend your hands and recieve your sin eater, this eats wolf food and must be raised by 1 level, while Sin eater is summoned it takes and xp/sp you earn. Return to judge when it has leveled and hey presto you lose 1 maybe 2 or 3 anything up to 10 pk's from your count.
Once you have 0 pk's you cannot raise another sineater until you have at least 1 pk, I recomend you keep 1 pk at all times, level a sineater and hand in when you have 5 or 6 pk's, this way you can pk alot.
Once you have done the quest you retain an item, if 1pk or more you can automaticlly hand in to gain a new sin eater, however if you fall to 0 pk's you must repeat the 1st part of the quest, yes IT 3 spiders.
NPC Started, Black Judge ( 3 or 4 in map, easy found in hardins academy).