I wouldn't rate it as an Ability. I'd run it that you have to do a quest EQUIVALENT in difficulty to that of an Esoterica (this is to avoid the fact that an Esoterica costs a Deity less than an Eternal to get an item that scales with you).Here's a tricky one I thought of: what would an ability that gives one an extra artifact be? I was thinking maybe make it whatever is an esoteric ability for the being's tier (so cosmic for immortals, transcendental for sidereals etc.)
For retry you intend reroll?Here's an odd one
Skill Retrial (Epic)
Prerequisites: 25 ranks in the skill in question
Benefit: You can retry the skill, even if the rules don't normally allow it. You must still wait an hour before each attempt
Special: You can take this feat multiple times. Each time, it applies to a different skill.
yesFor retry you intend reroll?
This is a good one. I never understood why certain skills disallow a retry. It's easy enough to come at a problem from a different angle after taking a break and giving it more thought. This feat should almost just be a houserule with no feat tax.Here's an odd one
Skill Retrial (Epic)
Prerequisites: 25 ranks in the skill in question
Benefit: You can retry the skill, even if the rules don't normally allow it. You must still wait an hour before each attempt
Special: You can take this feat multiple times. Each time, it applies to a different skill.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.