Walkthrough

The Most Truest of Basilisks is a Side Quest in Novigrad. Its not an official side quest but you will gain experience for completing it.

Travel Northeast of Oxenfurt Harbor near the bridge. There you will see a guy entertaining a group of guards with a caged Basilisks. But upon Geralt's further inspection its actually a Wyvern. The guards start to get upset with the entertainer, but before they can do anything the Wyvern bursts out of the cage.

The Wyvern is a level 10, but its only at half health, also they're several soldiers surrounding it so beating the Wyvern shouldn't be difficult. Use your Quen for extra protection and also use the firebolt potion to add extra damage. Once you kill the Wyvern the quest is over and you will gain experience..