You are given a power by a mysterious figure, but it came with hefty cost(s) or condition(s) that you were not aware of.
What is this mysterious power?
What is the cost(s) or condition(s) of having/using it?
No omni, almighty, meta, absolute, or nigh powers. The cost(s) or condition(s) cannot be removed, altered, countered, or negated, but can be "gotten used to" to certain extent.
What is this mysterious power? Fire manipulation. I can generate and the manipulate fire.
What is the cost(s) or condition(s) of having/using this power? When the sun goes down my body becomes enveloped in incredibly hot fire, causing a fair amount of pain and first degree burns but my body is constantly regenerating damaged tissue. This fire cannot be put out even if submerged into water. Pain meds do not help at all. This lasts until morning. I have gotten use to the pain so it is manageable but it still hurts a lot.