What are the extra icons that sometimes show up on Okami HUD during combat?

Solution 1:

The icons in the lower left corner of the screen represent the player's current Godhood level. Godhood allows the player to absorb enemy attacks without taking damage, with each increasing level allowing for one more negated attack.

By default, the player has neutral Godhood, which is not represented in the HUD (no icon will appear). This level does not grant any effects. When combos are performed successfully in battle, the player's Godhood level increases.

Godhood level is represented by a circular, colored icon containing a silhouette of Amaterasu in the lower left of the screen:

Neutral (no icon) -> Small red circle -> Medium-sized yellow circle -> Large green circle

Taking damage in battle will decrease Godhood by one level.

There is also a "negative" Godhood level, which is indicated by a skull-and-crossbones icon and can only be acquired by fleeing from battle (which will reduce Godhood to this level regardless of its prior level), or by entering a cursed area when at neutral Godhood. Some sources state that this level leaves the player especially vulnerable to attacks, but there does not appear to be any confirmation that it causes the player to take any additional damage compared to neutral Godhood.

Additional notes about Godhood:

• There are two items which increase the player's Godhood level: Traveler's Charms, which increase Godhood by one level, and Godly Charms, which increase Godhood to its maximum level.
• Godhood is explained in-game in a scroll obtained before the Spider Queen boss battle.
• Sometimes, when entering difficult fights, Godhood will automatically fill to its maximum level.