Hello and welcome to codecombat discourse! This is a cozy forum where you can share ideas, share fan art, get assistance for code, etc! Before you proceed, we hope that you review this topic, which shows all essentials of this board! Thanks!
@Tropicalz, you can summon burls with Vine Staff, which grants you the spell hero.cast("summon-burl"). In mountain levels, you get Boss Stars, which can summon (and command) commandable units such as soldiers, archers, paladins, griffin-riders, or artillery (not that the boss stars may be able to command them, but not summon them). Boss Star’s give you these methods of summoning and commanding, hero.summon("unit") and hero.command(unit, "action", target). Unholy Tome V grants you the ability to summon-undead (skeletons), with hero.cast("summon-undead).