This is the 3rd pantheon in the Godmaster content and IMO the first one that's moderately difficult. You have to face 10 bosses back to back with a Hot Spring and Bench halfway through (you can modify charms at the bench but progress is not saved).
1. Hive Knight
2. Elder Hu
3. The Collector
4. God Tamer
5. Troupe Master Grimm
Hot Spring and Bench
7. Grey Prince Zote (level 3)
The Godseeker NPC
10. Great Nailsage Sly
The only way to get through this is to practice and master each boss encounter, knowing their attack patterns and when it's safe to counterattack. In the main game it's often fine to flail through bosses and barely survive but to get through this pantheon, you need to defeat bosses with minimal damage taken. Nailsage Sly will likely prove to be the most difficult part since you've never seen him before
and because you have to spend 10 or so minutes just to get to him for a chance to learn his attacks
. EDIT: After fighting Sly (or any boss, for that matter), he is available to practice against in the Hall of Gods below the Pantheons.
For charms, I used Unbreakable Strength (extra damage), Quick Focus (faster healing), Stalwart Shell (longer invulnerability after taking damage), Grubsong (gain soul when damaged), and Longnail (extended nail range). Note that Fragile charms will not break if you die.
Here's a video of my successful run:
Further info can be found on the Hollow Knight wiki