1. Go to the Black Judge.
2. He send you to Magister Joan (Ivory Tower, 3rd floor). She asks you to bring 3 Trisalim Tarantula Venom Sac.
3. Go to Sea of Spores. Kill 3 Trisalim Tarantula. Go back to Magister Joan.
4. Go to the Black Judge. He gives you a pattern.
5. Bring that pattern and some materials to Blacksmith Pushkin (Giran) and receive a collar. (You need 1*Blacksmith Frame, 5*Steel, 2*Adamntine Nugget, 10*Silver Nugget, 10*Cokes) 6. Go to Black Judge again. Now he can summon Sin Eater.
7. You must rise up 1 lvl to Sin Eater.
8. Go back to the Black Judge. He decrease your PK counter random from 1 to 10.
Source : Lineage 2 stratics
Portal 
