My favorite characters in this series were Jung Jae Heon (Kim Nam Hee) with his samurai sword, Han Du Sik (Kim Sang-Ho) with his makeshift crutch gun, Cha Hyun Soo (Song Kang) with his electric spear/knife sort of thingy, and Pyeon Sang Wook (Lee Jin Wook) with his sheer anger and power. I love the creativity, innovation, and detail put in the storytelling, the characters, and the monsters alike. The monsters are not only elaborately done but quite intricately. It's almost like they mirrored each character's fear and apprehension. And in that sense, I liked that all the characters were flawed, each fighting not only literal monsters but the monster within, scars of life, scars if left to fester could turn them into the very monsters they fight in all its forms, be it the fear of loneliness, biases, anger, selfishness, grief, loss, injustice, prejudice, and everything else in between.

They say, sometimes human places create inhuman monsters. That's so true in that each of the characters starts out trying to survive the best way they know how individually, even if it meant using others for their own benefit or furthering their own survival. Still, along the way and in their fight to survive, they come to realize that they as humans are capable of the worst things possible and that they weren't just trying to survive but fighting for the survival of humanity, to not turn into the very monsters they were trying to survive. As said, it’s not the strongest or the most intelligent who survive but those who can best manage change. I truly enjoyed this show and the accompanying OST; very well done.

Character-wise:
Lee Shi Young was exceptional in her role, but that's nothing new as she’s always great at whatever role she plays, but I have to say I was very impressed by how fit she looked as Seo Yi Kyung, the firefighter fighting her own demons. There were quite a few hard to stomach characters; Lee Eun Yoo (Go Min Shi) and Eun Hyuk (Lee Do Hyun) were among those. The two of them were the most selfish, each for their own struggles but at the same time, were the ones with the most character development, in my opinion. However, I must note Eun Hyuk embodied the leader role very well towards the end; seeing that development in him made me realize he was so selfish but more pragmatic in his bid to protect their only shelter from the dire world outside.

The most inspiring character was Jung Jae Heon both for his grounded belief in what's right but also for his courage and conviction in not once wavering between what was right vs. what was wrong. In a way, Sang Wook was a mirror of Jae Heon in his determination paid or otherwise to brutally dispensing justice. The two characters that brought the most depth to the series other than Sang-Ho were Kim Gab Soo as Ahn Gil Seop and Go Yoon Jung as Park Yu Ri Gil Seop's caregiver. Indeed a great source of inspiration and motivation to the struggle. On the other hand, Sang Ho's character was the most profound, not just for the powers he amassed from being infected but also for breaking the chains and labels society consciously and sometimes unconsciously puts on everything and every one different out of fear or ignorance. He was the doorway to the true examination of human monstrosity and humanity's embodiment from a monsters' perspective.