The gems of might and magic

The gems of might and magic refers to ancient, magical artifacts thought to have played a major part in the early power distribution across the lands of Epora. They resemble gems, about the size of a grown mans fist, and they have a faint glow and a rather strong magical aura, making them incredibly hard to hide from those who know where, and how, to look. As far as the knowledge goes, there's only ever been three different gems recorded. It is assumed those three are indeed the only three artifacts of this kind.

The three gems possess one strong aura each, and they have very different uses. If a gem is not held, or in physical possession by anyone, it's radius will increase tenfold, and only the last mentioned aura effect will be active.

The soldier's gem
The soldier's gem is red and made to empower the holder by weakening the others around him. It's aura will weaken and exhaust the unfortunate opponents of the holder. The soldier's gem got an effective radius of 60 feet. It does not affect the holder.

Any creature in range got a -2 damage penalty on physical attacks.

Any creature that end its turn within range must roll a constitution saving throw. A failed save will apply one stack of exhaustion, up to a maximum of two stacks.

The wizard's gem
The wizard's gem is blue and made to empower the holder by draining on the arcane powers of any nearby creatures. It's aura will lower the magical potency of spells and silence the enemies. The wizard's gem got an effective radius of 120 feet. It does not affect the holder.

Any creature in range got a -2 damage penalty on magical attacks.

Any creature that end its turn within range must roll an intelligence saving throw. A failed save will make the creature unable to speak until the end of its next turn, and hence cannot cast spells with a verbal requirement.

The commander's gem
The commander's gem is yellow and made to empower the holder by magically charming the surrounding creatures. It's aura will grant disadvantage vs. the holder, and charm the attacker. The commander's gem got an effective radius of 60 feet. It does not affect the holder.

Any creature in range got a disadvantage on any rolls AGAINST the holder.

Any creature that end its turn within range must roll a charisma saving throw. A failed save will make the creature charmed by the holder until the end of its next turn.