Every roleplaying game has a boss that causes major headaches due to their damage resistance and damage output. To make your playthrough easier, here is my Galerius boss guide for Unicorn Overlord.
Galerius Boss Guide – Unicorn Overlord
Galerius is highly resistant to physical damage and can wipe you out with a single blow. Place your Thief up front so he can dodge Galerius's blows and deploy Mage units to deal magic damage to him. You'll need to recruit some units outside of the main story to do this though, so be prepared for some grinding.
Galerius is the main antagonist of Unicorn Overlord, and the first major battle in the game involves an encounter with him. He is incredibly difficult to defeat, as he is almost completely immune to physical attacks. Additionally, he can reduce the HP of an entire party to one point, and his armor neutralizes the first two attacks he receives. As if that wasn't enough, he is accompanied by two knights, who are much weaker, but can respawn when his garrison completes a heal.
Related: What Difficulty Should You Choose in Unicorn Overlord – Difficulty Difference Guide