Opinicus is a very powerful archgriffin living in the forests east of Oxenfurt. Many mercenary companies in the past have tried to take down this beast, but to no avail.
Bestiary entry[]
Thin rachides, sparse after feathers... An archgriffin. – Geralt of Rivia
Killers of various stripes - mercenaries, knights errant, ambitious lawmen - try at times to compete with witchers as monster slayers. This usually ends in a massacre that not only does not solve the problem, but in fact only makes it worse - the beast walks away from the fight unharmed, enraged and out for vengeance. Such was the case in the mountains outside Oxenfurt, where a powerful archgriffin had made its nest.
Once again it fell to the witcher to clean up after amateurs. He knew neither Igni nor bombs dealing fire damage would have any effect against this fire-loving creature. He would also have to look out for its acid, which can eat through even the thickest armor - leaving one vulnerable to its razor-sharp talons.
After a long fight, the witcher slew the archgriffin. Some scholars in nearby Oxenfurt might accuse him of having contributed to the disappearance of an endangered species and disrupting the local ecosystem. Somehow, the witcher didn't seem likely to lose much sleep over the matter.