Summon Unit Question [FE8]

How can i Summon a unit on a level that is selected on the preparation screen using event assembler? I am hacking the FE8

… I think you’re going to have to further clarify exactly what it is you mean. Do you mean “Summon” as a summoner does? Because you can’t do that without (likely) some advanced code; summoners can only summon their phantoms.

i need to put an Ally that the player can select on the prepare screen. On the game when you enter to the prepare screen you can select what characters you will use, i need to make this.

You simply need to load the unit as a player unit any time beforehand.