Eradis Absorb Magic Tattoo

The tribes of Eradis have several tattoo patterns not found anywhere else in the world. These patterns allow the person to absorb energy directly from the environment. There are three different patterns, light, heat, ambient. There is a drawback, the tattoo is always active. With the light tattoo, when the tattoo is exposed to light it generates magic. The person absorbs the light that strikes their skin, and it is converted to magic internally. They can then use this pool of magic to power their other magic tattoos, or any other type of magic they know. The light tattoo is the least dangerous and the easiest to control. The person can cover the tattoo with clothing to block the light. If the person absorbs more magic than they can control they will be damaged. The light tattoo absorbs at a low, but constant rate in direct sunlight. There is also a change to their appearance. All light that strikes their skin is absorbed, causing them to appear as a flat black void, in the outline of a person. This can be mitigated with clothing.
The light tattoo can be very useful in some situations. The person uses it for endurance running. The steady inflow of magic allows the person to run all day, by using the energy to power their healing, toughness, and strength tattoos. With twelve hours of daylight the person runs 180 miles, normal person marching can cover 30 miles.
With the heat tattoo, when the tattoo is exposed to heat it generates magic. The person absorbs the heat that strikes their skin, and it is converted to magic internally. The tattoo is only activated when the heat is greater than human body temperature. They do not freeze water by putting their hand into it. They can put their hand into a campfire and gain power from the heat hitting their skin. The amount of magic absorbed is dependent on how hot the source of heat, and how much skin is affected. Sources of heat in general give far more magic power than sunlight does for the light tattoo. Sources of heat can be more difficult to locate than sunlight though, and often are not mobile.
If the person absorbs more magic than they can control they will be damaged. It is easier to be damaged by heat, the power source give more magic energy quicker. Also it is harder to block incoming energy that in unwanted. With the light tattoo the person can put on clothing, or get in some shade. With the heat tattoo there is no blocking the heat, if it is greater than body temperature it gets absorbed.
The heat tattoo can be very useful in some situations. The person has trained to be able to contain a large internal reservoir of magic. Before a battle they stand naked in a campfire and fill their reservoir. They go into battle, and draw on the reservoir for incredible boosts of strength, and healing. Their reservoir starts to get low, and they smash a nearby oil lamp over their head. The burning oil does not injure them, it allows them to keep fighting by filling their reservoir.
With the ambient tattoo, the person is always absorbing a trickle of magic from the ambient. The amount is generally less than the light tattoo in daylight. Anyone can learn how to absorb magic from the ambient, at the cost of effort and will. The ambient tattoo allows the person to always be absorbing magic from the ambient, effortlessly.
Like the heat tattoo there is no blocking the absorbing. The amount absorbed is dependent on the amount of magic in the surrounding ambient. This tattoo can be very safe the majority of time. There are some situations that can make the tattoo difficult, or very useful. If the person steps into a leyline they will be damaged. People naturally block absorbing from a leyline, but the tattoo will automatically draw energy from the leyline. Far more energy will be absorbed than a person can safely handle.
Different locations have different levels of ambient, some areas much higher than others. It is possible a forest could have a much higher level of ambient, causing the person to absorb much more magic than normal. The person could remain for a few hours or minutes, depending on the magic level and the person. To remain longer the person would risk damage.
The ambient tattoo can be very useful in some situations. A person that is hunting an essence magic user. The more magic the opponent uses, the higher the ambient magic, and the more energy they tattoo is able to absorb. The essence magic user weakens themself with the use of their magic, and causes the ambient tattooed to grow in power.
By absorbing magic a magic user can fill their internal pool beyond its natural level. It requires effort to maintain the hold on the additional magic, the greater the amount, the greater the effort. Losing control of small amounts over the pool is harmless. The additional magic dissipates into the ambient. Losing control of a large amount can cause changes in the magic user, magic effects and mutations. Losing control is also damaging and painful, the magic ripping its way out of the body causing burns. If the amount of magic is great enough the person will be incinerated.
The changes may be wondrous, horrific, or just odd. Examples, any room he enters develops a noticeable chill, or all his hair falls out and he develops very fine scaled patterns on his skin, his eyes become solid metal they function just as regular eyes or better, but give him pain when it is cold, and may unnerve some people, or develops a craving for eating metal, only a coin or two a day, and his body processes the metal into the hair he grows on his head. Or very minor the skin beneath his fingernails turned black, his irises changed color, or his hair, or cats now hate him.