The portal will take visitors to Greyoll's Dragonbarrow an area

To begin, go for the Third Church of Marika in Limgrave--it's located east of the initial Sites of Grace. Then, you have to travel northeast until you see an open portal in the middle of the ocean Elden Ring Runes. This is in fact connected to a side quest that you'll receive for a character later on, however, getting them to do it first isn't mandatory.

The portal will take visitors to Greyoll's Dragonbarrow an area of high-level located to the north of Caelid with one of the game's most bizarre characters. They'll be immediately behind you once you arrive. The area is an opulent site. Be on the lookout for the large creature on the stairs ahead of you as you go out, because you won't want to mess with it.

Outside, you'll see smaller, relatively weak enemies, and beyond them there's a bridge with a place of grace adjacent to it. Take the grace site If you wish however, don't cross the bridge. Instead, return towards the smaller enemies since they're the ones you'll be farming.

These guys can be killed quickly. While a magic build will be beneficial here, melee character can stagger them and use stealth. The video claims that you'll get 637 runes per kill and there are several, but upon checking it.

I discovered that I actually received significantly more: 1094 ranes per kill. The site of grace will let you refresh them buy Elden Ring Items. Make sure you don't give them an opportunity to retaliate, as they are able to kill low level characters in one hit.