How to complete Gatekeeper Gostoc’s questline in Elden Ring

gamepur.com:

Gatekeeper Gostoc is one of the earliest NPCs you will come across and possibly the creepiest. He doesn’t offer many reasons as to why you should continue his questline. He constantly steals your Runes while you are in Stormveil Castle, he locks you in a room, and he stalks you. Not necessarily the nicest person you will come across in the Lands Between. Of course, he still has a questline that you can follow and if you are trying to complete it, you will want to know the steps. Here is how you complete Gatekeeper Gostoc’s questline in Elden Ring.

Gostoc first appears in Stormveil Castle next to the main gate. Once you defeat Margit, go through the door to the left of the large main gate and Gostoc will call you over. He will warn you not to use the main entrance since it is tightly guarded and tell you to take the side path instead. You can choose to accept or deny his offer. If you accept it, he will wish you luck and send you on your way through the side path. If you reject his offer, he will call for his friend to open the main gate for you. Either path continues his questline but we suggest taking the side path.

After progressing through the castle a bit, you will come across a room with the Rusty Key in it. Once you enter this room, you will hear Gostoc’s laugh and he will lock you inside with a Banished Knight. It is okay if you die here, but try not to because Gostoc will take 30% of your Runes. While going through the castle, you will find Gostoc stalking you in various places:

If you spot him in any of these locations and talk to him, Gostoc will give