The Ice King is one of the most tragic characters ever written in recent times right next to Gollum. When you consider he was pivotal to how the Earth survived and how he protected a main character throughout childhood at a great ongoing personal cost - its astoundingly deep. The lore/universe is also very imaginative in the right way (somewhat grounded but very creative). Highly recommended. Watch Season 1 and 2 before judging because S01 is a little rough.