A cutscene will occur as you enter the fog wall as part of Siegward of Catarina 's quest. This fight will be extremely easy with Siegward’s help, as he can defeat Yhorm on his own by using the Storm Ruler’s Weapon Skill.
If Siegward is not aiding you in this fight you’ll need to rush to the back of the area and grab the Storm Ruler near the throne and equip it. The blades Weapon Skill allows you to charge the weapon until it begins to glow and then release it to bring Yhorm to his knees.
The blade must be fully charged to do the full damage and you don’t need to use the skill right away after it is charged, so feel free to dodge to avoid any attacks. With this strategy you’ll only need to focus on dodging in between each of the Weapon Skills attacks to finish Yhorm.
List of Yhorm’s attacks:
- Battle Cry: Roars, creating a shockwave that knocks you over
- Kneeling Strike: Steps forward and strikes the ground, kneeling in the process
- Backhand Slash: Sweeps the machete from back to front in an upward strike
- Turning Swipe: Performs a sweeping attack while turning around to strike
- Charge: Grabs the machete with both hands and charges forward in a linear path
Drops: 36,000 Souls , Cinders of a Lord , Soul of Yhorm the Giant
After defeating Yhorm pick up the Storm Ruler , if you didn’t do so in the battle, and then speak with Siegward for a Siegbrau .
You’ll then be teleported to Emma, High Priestess of Lothric in High Wall of Lothric, but if you return to Yhorm’s bonfire you can pick up Siegward’s Storm Ruler , Pierce Shield , and the Catarina Armor Set .