To answer my own question, not quite. I remembered there were a couple of points I'd like to nail down for
Create Fire Elemental, namely the cost in Actions and the range.
The current rough draft has:
Create Fire Elemental (Costs # Actions). The fire archomental's hit points are reduced by 25 as part of it separates to become a fire elemental with 102 hit points. The elemental appears in an unoccupied space within ## feet of the fire archomental and acts on the archomental's initiative count. The archomental can't use this action if it has 25 hit points or fewer. The fire elemental obeys the fire archomental's commands and fights until destroyed.
I believe the old D&D Beyond version had:
Create Fire Elemental (Costs 3 Actions). The fire archomental's hit points are reduced by 50 as part of it separates to become a fire elemental with 102 hit points. The elemental appears in an unoccupied space within 15 feet of the fire archomental and acts on the fire archomental's initiative count. The archomental can't use this action if it has 50 hit points or fewer. The fire elemental obeys the fire archomental's commands and fights until destroyed.
Now 3 Actions is fine by me but I'd consider 2 Actions if you'd prefer. A single CR 5 Fire Elemental isn't that great an assistant.
Five yards seems a bit too short a distance though. A standard
conjure elemental spell has a 120 foot range.
How about the fire elemental manifests inside the archomental's
Fire Aura? So it's normally 30 feet, but it can create an elemental within 60, 80 or 100 feet if it uses
Stoke Aura.
Speaking of which, I was going to put a duration on
Stoke Aura but forgot. Meant to put a "start of the archomental's next turn" in there somewhere. Will do that in the next update.
Also, should we place a limit on how many created elementals the archomental can have under its control at any one time. Like, say four, and if it creates a fifth it must release one of the existing elementals from its command, transforming it into a regular fire elemental.
Oh, and I updated the
Fire Archomental Working Draft.