The Dragon Cult incantations are very powerful spells that you can find in the Lands Between. Among these spells is the Dragonbolt Blessing incantation. This incantation allows you to bolster your body with lightning, causing attacks to become easier to deflect. You also gain an increase in all ailment resistances while this incantation is active. The downside to this spell is that your lightning damage negation is reduced during its duration. Here is how you can get the Dragonbolt Blessing incantation in Elden Ring.
To obtain this incantation, you will need to make your way to Altus Plateau. This is the area to the north of both Limgrave and Liurnia. To reach this area, you will need to obtain the two halves of the Dectus Medallion from Fort Faroth and Fort Haight. After obtaining both pieces, you can use the medallion on the Grand Lift of Dectus in northern Liurnia to reach the plateau. If you are strong enough, you can also attempt to traverse the dungeon in northern Liurnia at the end of the ravine. This will also lead you to the plateau.
Once you reach the plateau, make your way east to the outskirts of the Capital City. Take the path north once you pass the first wall, and leave out of the northern gate. From there, follow the road to the south that leads along the outer wall of the city. This road will lead you to the Sainted Hero’s Grave. Go to the south of the Sainted Hero’s Grave to find the Stormcaller Church that is marked on the map above. Inside the church, you will find a chest near the entrance that contains the Dragonbolt Blessing incantation.