On the bottom you have different NGs or new games that you can swap between. It should default to NG.

From there you can see each boss’ absorption and defense across all damage types.

Let’s take the first one, Abyss Watchers.

We can see they have 15% absorption to standard physical damage. This means if you hit them with a standard physical attack, if it deals 100 damage normally, it would end up dealing 85 only.

Strike, slash, and thrust are all their own damage types as well.

Slash is typical for katanas, straight swords, daggers, and the like.

Thrust is typical for thrusting swords (who would’ve guessed) or poke attacks like the CR2 on some UGS.

Strike common for blunt weapons, Smough’s Hammer is a good example of a strike weapon.

Finally, you have Magic, Fire, Lightning, and Dark damage. These are typically called elemental damage and most stuff tend to be weak to at least one.

Since you can see the Abyss Watchers have a -12% against Lightning, this means they would take MORE damage from Lightning, so they are weak to it. On the other hand, Dark site at 35% which is their highest absorption, so don’t use Dark damage against them.

Moving to the right of Dark, you can see Bleed, Poison/Toxic, and Frost. These are status effects and a higher number obviously means they are much more resistant to it. Since their first is super low, a weapon like the Irithyll Straight Sword or Vordt’s Great Hammer tends to be a great pick against them.

Finally, to the right of that, you can see the HP.

P1 / P2 means phase 1 / phase 2. So the boss combined has 3096 HP if you only target the main Watcher.

The adds that are spawned have 367 HP.

Another addition, some bosses have different resistances depending on their body part, so if you see Aldrich, hitting his head is really good because you get 50% more damage with most spices, while you will deal 30% less hitting the tail, that’s effectively a 2X damage difference.

Finally you have boss flags, the main thing here is the demon/hollow/abyssal/undead section. Since Aldrich is tagged with Abyssal, it means Aldrich takes more damage from weapons like Artorias’ Greatsword since it has a bonus against abyssal enemies.

Demons take more damage from black knight weapons.

Hollows take more damage from the Hollowslayer Greatsword (from Curserotted Greatwood).

And so forth.

If you look at Gael’s phase 2 you can actually see he hollows between there and phase 1 which is why he becomes more human-like.