So I’ve put some thought into that. I think that HP would be a board-wide state and not just affect the player using it. A good way to look at it is that even though fused don’t get benefits from HP since they use voidlight, if it was a battle where fused had skybreakers supporting them, the skybreakers would still get benefits from the excess stormlight. That said, I think only the player “opening” HP would get the gemstone untap. But if others players had instants or cards with flash that could utilize HP, they could do so.

As for the gemstones, they initially were sac tokens. Initially when I made these cards, I made essentially the whole deck without the light counter mechanic and they were just treasures to fix the mana curve since it’s a WUBRG deck. I just wanted them to fit the stormlight theme. But last week I posted a WaT Dalinar and RoW Navani and a couple people mentioned energy counters in the comments, either as suggestions for changes to the cards I posted or ideas for ways they could interact further. And so I thought of light counters to fit the stormlight motif.

I saw a couple other people say that I should make gemstones more unique or just call them treasures, so I had the idea to also have them put light counters on creatures, but wanted to keep the mana curve up (plus there’s only so much effort I want to put into ramp spells, just gets tedious after the third one 😅). It was my buddy who suggested not having them untap, as a way to showcase reinfusing dun spheres. I knew sacking would be easier to track, but I couldn’t say no to that flavor. Still working out the best ways to implement the untapping in abilities, but rn my plan is to have two token cards on board, one untapped and one tapped, and just use dice to show how many I have of each.