How to rematch Grafted Scion in Elden Ring

gamepur.com:

First-time Elden Ring players are meant to lose the first boss fight against the Grafted Scion just after creating their character. Doing so transports the Tarnished to Limgrave and the Lands Between proper, opening up the whole world to explore.

This time, though, revenge is possible. The Grafted Scion’s arena exists in the game world, and it’s possible to return for a rematch. It won’t happen immediately, as the portal to the island is part of the Four Belfries area in the northwest of Liurnia of the Lakes. The hill where the Four Belfies sits is likewise to the northwest of the Raya Lucaria academy.

Activating the portal requires the Imbued Sword Key, one of which rests in a chest at the highest of the Belfries. Just down the hill to the southeast of the Sword Key chest is a portal with a message near it reading “Precipice of Anticipation.”

The Precipice portal returns Tarnished to the area beyond the Grafted Scion’s boss room, with the fog gate active. Passing through the golden mist begins the rematch with the Scion, but those who choose to make the trek back will find their experience and better gear serves them well against the first enemy that overcame them.