Actually you CAN make a non commander unit out of the Communicant. The Communion Slave ability is not a #onebattlespell type ability, it is directly tied to the unit number.
So basically you can overwrite the Communicant with your unit name, stats, sprites etc maintaining the same unit number. The downside is that the unit will not count as a communion slave in a communion, but the cool thing is, the unit will receive any self casted buff the communion masters cast just like a communion slave in a reverse communion.
It makes for a really cool unique unit. I overwrote the communicant with a sliver unit that gains abilities from specialized slivers that autocast communion master at the start of battle. It turned out pretty cool
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