Witches exist at all levels of society, including the top echelons. These individuals summon the orgone within themselves to perform various feats of magic through invocations. One brand of magic revolves around battle. These attacks can be very powerful, and consist of magical attacks and defenses. Some are designed to focus on a particular opponent, such as fireballs and beams of energy. Others are geared toward an entire area, such as lightning storms or small tornadoes, which can kill dozens if not hundreds of people. Still others focus completely on defending the user, such as magically generated shields or protective spells. Battle magic is powerful, and can turn the tide in war. However, they have some limitations which can effect their success.
Invocations can last anywhere from 30 seconds to 5 minutes depending on the type and Power of the attack. They last for various durations. Some can be used repeatedly with the mage keeping the spell active by using a shorter version of the incantation (energy blasts, fireballs, etc). Others are one-shots, and the mage must start over from the beginning to use a second time.
Battle magic requires a certain amount of orgone from the witch. The cost is determined by the power or length of the spell. Orgone replenishes over time at different rates depending on the user.
Mages must be relatively close to the area they wish to target. They can be separated only by a few dozen feet in order to be in range, or the attack won't hit.
Basically, witches can be walking, fleshy tanks, and are very valuable to their societies. However, they can also be targets for assassination or sabotage by other rival covens or states. Therefore, they are often heavily protected by shield guards. The job of these guards is to keep their witch alive, and protect them while they are performing their invocations. They can range from one to several, depending on the importance and wealth of the witch.
It would be common sense for witches to use other witches to guard them, as one can focus on defense while the other on attacks. This would provide for an impenetrable combination. However, shield guards are always magic less. Instead, they use regular weapons to protect their wards.
Why would witches not use lower-tier witches to defend them and entrust their safety to non-magic users?