Trying to Create a Tag
 

I'm creating a variant of the Aboleth sorcerer bloodline from Kobold Press's Deep Magic. I want to be able to use the Mythic Sorcerer ability Mythic Bloodline (Power) with it.

I've figured out that I need to create an ability on the General/Ability tab. I used a copy of the Psychic ability (xLGSorPsyc). (I'd have used the Aboleth bloodline, but it's not set up for Mythic Bloodline (Power), either.) I changed the IDs of the abilities that are modified in Eval Script #2. I changed the Tag ID for Group ID: LGMyAblDep to cSoSasAbo, which is the name I gave that bloodline. It is in all other ways identical to xLGSorPsyc. The unique ID is xLGSorSasAbo.

I also figured out that I need to create a replacement for the Class Custom Ability Mythic Bloodline (Power) (cMArMyBloo) because I'll need to add a bootstrap and I can't just edit the ability. I created cArMyBloo that replaces it. I then added a new bootstrap for the bloodline with Thing: xLGSorSasAbo. Under Conditions, I have LGMyBlood.cSoSasAbo, with timing of First/110 which is the same format as all of the other bootstraps.

There is another Custom Ability (mcLGSorBPo) that appears to be redundant to cMArMyBloo, and it doesn't appear to be used. I added cSoSasAbo to it as well.

When I try to compile, I get an error:
I cannot figure out where the tag is supposed to be defined. Except for the changes in ability IDs and the bloodline's ID, everything is identical to the Psychic bloodline, which works just fine.

On any thing you've defined in the editor (your new bloodline is probably best), click the Tags button on that thing, add a new tag, and enter this tag.

There's two big steps to running a character in HL (and the compile process is set up to test things in the same way) - first, HL loads the database of everything that's defined in this game system - so it knows about everything created in the editor, and every tag, field, etc. on those, and then it starts running scripts, evaluating whether bootstraps should be applied, etc. So the tag needs to exist somewhere in that database of all possibilities for that game before something can make use of it in a script or candidate expression. LGMyBlood.xLGSorPsyc is defined in a separate file that isn't accessible to users, rather than on the bloodline thing, but defining it on the new thing you've created should get around that.