Summoned to Another World with My Class, But Banished for Being Useless, I Use the Skill [Necromancer] to Command the Strongest Servants and Build an Unstoppable Army. I, Myself, Powered Up, Eventually Becoming an Invincible Being

We were summoned as a class to another world. Apparently, our entire class was chosen as heroes to defeat the Demon Lord targeting this world. Each of us received one hero skill. The skill I received was [Necromancer] , which only allows me to make low-level undead, or my Servant. It was the weakest and most useless skill in the entire class, and I was banished as a “worthless”. However, my skill soon advanced to the next stage, evolving into the strongest skill!