Once you’ve made your way through most of Irithyll of the Boreal Valley you can engage in a boss battle against Pontiff Sulyvahn. There are two NPC summon signs (Anri of Astora and Londor Pale Shade) in the small alcoves on the balcony just outside the entrance to the boss area. You can’t rely on staying behind Pontiff Sulyvahn like you can other bosses, so you may want a bit of help with this one if you have an active Ember.
Pontiff Sulyvahn uses two weapons, a flame sword and a sword covered in dark magic. He has a variety of attacks that cover almost a full radius around him, making it difficult to stay behind the boss and still avoid attacks. That said, your best bet is still to try to get behind Pontiff, but be ready to block or dodge an attack as soon as he flinches.
The boss has a number of different attack comes that vary in length and speed, and come at you randomly. It’s difficult to nail down a pattern for this boss, so continue to roll and occasionally block (you’ll still take some damage even if you have a 100 percent physical damage shield) until you see Pontiff Sulyvahn pause his attacks. When this happens, strike as many times as you can during this short period between combos. Depending on your weapon, you will likely only get between one and three hits off before Pontiff starts another combo.
Once you get Pontiff Sulyvahn to approximately 50 percent health, he knees down and sprouts wings. While you have time to get in one or two attacks here, he follows this with an explosion that will heavily damage you if you’re too close. Unless you’re right next to Pontiff when he knees, it’s best to play it safe and stay back.
During the second phase of the battle, Pontiff retains all of his combo attacks from before and adds two projectile attacks. If he fires a straight beam at you, it’s easy enough to dodge left or right. However, if he fires a horizontal beam, dodge forward, rolling through it. Timing is important to make sure you roll through the beam and don’t get hit.
With Pontiff’s new wings he adds two aerial attacks. If the boss jumps into the air, move away quickly to avoid the dive or ground slam attack that follows. If Pontiff hovers for a short time, the dive attack is coming which will target your character. Wait for the dive, then dodge out of the way and attack quickly while Pontiff is recovering from the dive. If the boss isn’t in the air long, it’s the ground slam and he will drop straight down with a wide area attack.
The biggest change in phase two is that Pontiff will summon a clone that copies all of his attacks. If you see the dark sword pointed straight up, Pontiff is about to summon his clone. You can attack him while this is happening, but as soon as the clone appears you need to kill it. The clone doesn’t have a lot of health, so it goes down quickly, but if you let it linger this becomes a very difficult battle. You will have to dodge two sets of attacks from an already aggressive boss.
Defeat the boss to obtain the Soul of Pontiff Sulyvahn, then light the Pontiff Sulyvahn bonfire. At this point you can continue on to Irithyll Dungeon, or you can proceed forward to finish what’s left of the Irithyll of the Boreal Valley area and find the entrance to Anor Londo.