Here’s how Elden Ring spirit ashes (NPC summons) work

destructoid.com:

Elden Ring spirit ashes are like solo co-op AI partners: it’s as simple as that. But there’s a few nuances as to how they actually work.

So at the start, you can get them in one of two ways.

So you can only summon spirit ash companions in specific areas. Generally, these are around world bosses or in boss arenas (with exceptions, typically world boss arenas like gaols).

The rule is that if you’re in an area with a named enemy to fight, your spirit ash item (which you have equipped to a quick slot or a d-pad slot) will “light up.” This indicates that you can use it. Diving deeper, you can use them when in the proximity of a rebirth monument (a statue in the open world).

Once you do use them and they’re successfully summoned, you cannot re-summon them until you rest at a site of grace (bonfire). So you can’t spam NPC ally summons, even if you have the FP (MP) to do it. This is important, because some spirit ashes cost so much FP to summon that they’ll actually gate you from using them if you don’t have enough maximum FP to support the actual use of them.

You can buff or heal them, though, so remember that if you have a build that can cast AOE buffs.

You need to pick up Glovewort items, which are generally found in crypts.

If you find yourself heavily using NPC spirit ash summon builds, or relying on them a lot, make a point to visit crypts, and pick up everything in them, including the flowers on the ground (they usually light up).

With these crafting materials in hand, you’ll be able to upgrade your summons with Roderika, the Spirit Tuner, back at the Roundtable Hold hub. She’ll set up shop next to the blacksmith, Smithing Master Hewg, but first, you’ll need to talk with her and Hewg several times. Look for a unique