Magic
The Pentagram Ring lends itself to holding a wide variety of intentions, or whatever Magic you create for it.
As with any work of this sort, the adage of "Do what thou wilt, but that you harm none" applies. There is always danger in holding power over others. The law of threefold return generally discourages those that might abuse power, but it is worth repeating here, lest any forget.
A wide variety of intentions can be held in a ring, limited only by your imagination.
Likewise, the Celtic Heart Ring can be used for Intentions. Usually people focus the use of this ring on Love.