A good way to make the ability both more flavorful and more mechanically interesting would be if the emblem worked more like the monarch, with only one player able to have it active at a time. There’s only one ring, after all, so if your ringbearer dies then your opponent gets the ring and their emblem turns on while yours turns off. Having the ring would also require having a creature to hold it.
And every time you’re tempted while you have the ring, your ringbearer gets a burden counter (as used on the one ring card) and once you hit the final level of temptation you have to pay life equal to your ringbearer’s burden counters each turn, or they’re sacrificed and your opponent gets the ring and a wraith creature token which becomes their ringbearer.