Is this possible to add fourth chosen (using xcom legends charon models)?

hmmm.... charon even ported as cosmetics already

Xcom legends legion character assets (from skrimisher faction) model also good choice for artillery chosen

Maybe use aliens models for new aliens from xcom legion (muton, andromedon models already available)?

Sadly xcom modding isn't in a state yet if ever be to add new chosens (or they are keeping any sign of progress of it very hidden). It mostly comes down to just how much steps and coding needs to be done just for the game to not implode on itself with even an attepmt of that, also not to even mention the balancing of it.
But hey we can allways hope it'll become a reality in the future.

Originally posted by 45fg45:

Is this possible to add fourth chosen (using xcom legends charon models)?

it can technically be ruler :) those can be done

Well if were talking about a fourth chosen, wasn't a fourth chosen unit called Zealot found in the game files that was meant to be a dark reflection of the Grenadier Class spliced with elements from the Specialist Class?

I also agree with Shaggoth, you could make it into another ruler, like TeslaRage's Spark Ruler, RealityMachina's Avatar Ruler and Raze's Corrupt Avatar.

rulers aparently easier to make, at least we know some, listed above :) also hive queen. as for zealot, i'm going to google it >_>

Is there a chance to add a Spectre unit for the Requiem Legion?

Xcom Bio Division mod already contain ported mechtoid model, are you planning to work with that ready assets?