What about a Ring of Elythara?Zukero: Your quest sketch looks fine for a first draft though (we can discuss it further if you decide to open a dedicated thread, as we're getting off-topic here), and I see no reason not to keep it up, despite the reward being something else than the RoLS. It could still be an interesting ring that we have yet to create.
As we like choices in AT, that "rusty ring" could be revived in two different shrines, requiring different offerings to complete, ending up with two different but comparable rings...
It has a high resistence to damage and negative status effects and can infect your oponent when the characters infected.
I even thought of a special effect when combined with RolS like when HP falls under 20 % of maximum, the healing effect of RolS is doubled for this fight, negative status is healed completly and using items will cost 3 AP instead of 5.
The other stats should be complementary to the ones of RolS.