It's probably a nostalgia for actor Shin Eun Kyung, seeing how she worked with the writer and the director for The Last Empress and The Penthouse., and being in the set that looks like The Last Empress and acting the same character roles.
Basically, the grandfather is staying aloof with the FL, so he can stay focus on his quest in proving the Assemblyman…
Yep. He did things for a reason, and a very valid one IMO. I mean, if you are going to suspect a powerful person, it's always better to keep everyone else at arms length to avoid getting them involved. But deep inside, it's painful and very heavy.
Mr. Time Stop who transferred to a different school.
They hid his face, which means, he is probably still around and we probably saw him in earlier episodes too.
That student probably knows a lot, as in, a LOT. Mr. Time Stop seems to be observing. I think he only made it appear that he is unqualified and transferred, but in reality, he is still in the school, watching, observing.
Another thing, when he stops time, it seems he has another ability, manipulation or convincing. Because after he stopped the time, the PE Teacher changed his tone; instead of convincing the student to stay, he just agreed.
Mr. Time Stop did something during that period he stopped the time. He changed the PE teacher's mind.
So, if a child's parents are both superhumans, the child inherits both. Like Mr. Flying Kid also have super hearing like his mother.
If only 1 parent is superhuman, the child is 50% superhuman. Ms. Self-healing doesn't have the physical strength of her father, that is also common with 100% superhumans. She only inherited her father's self-healing.
That means, Mr. Electric Bus Driver, also only acquired his father's electric powers but not the physical strength and speed, that's why he was easily defeated with his first encounter.
It also explains what they were talking about when they were looking down on the American hunter (in the early episodes), because the 100% superhumans understood the secret of being children, to be 100% superhuman descendant, both parents should be superhuman too, otherwise, they're 50% only.
Eventually it gets diluted.
It also appears that a descendant acquires the main ability of their parent, the first to be sacrified is physical strength and physical speed. Maybe, if they train well for years, they can gain a portion of their missing strength and speed.
The real question now is, how did superhumans started in the first place? From what the North Koreans hinted at, it was because of one South Korean that the NoKors started to develop their own superhuman program.
That implies, it's all about blood and genetics.
If so. Who was the first superhuman? And who spread the genes?
Basically, the grandfather is staying aloof with the FL, so he can stay focus on his quest in proving the Assemblyman killed his daughter.
If he started to build his relationship with his granddaughter, he might start thinking to let everything go “for the sake of his granddaughter” and not achieve justice for his daughter's death.
That must be very hard for the grandfather. He had to keep her daughter's only child at arms length just to keep going with his investigation. The granddaughter who keeps reminding him of his daughter. The granddaughter who can make him happy because, in a way, his daughter lives in her.
But, he has to do it to keep his resolve, as well as to protect her and his other daughter.
That was a good background story for the grandfather. I like it.
And how they showed the grandfather cares so much about his granddaughter when she showed up with blood over her, also revealed how much he cares about her, and how he was just forcing himself to keep her at a distance. That moment, he was crushed.
Which was also no doubt the reason he turned his investigation over to the police. When he saw his granddaughter with blood over her (and probably ignored him as well), he realised he has no more time in the world and yet kept his own family away from him. That even though he cares so much about them, his investigation has consumed him and it cracked their relationship.
Great writing for me. It's not every day that you see something this deep as a background story for a support character. It's deep and meaningful. It makes us think, “would I make similar decisions if I am in a similar situation?”
1 
They have an ace student.
Mr. Time Stop who transferred to a different school.
They hid his face, which means, he is probably still around and we probably saw him in earlier episodes too.
That student probably knows a lot, as in, a LOT. Mr. Time Stop seems to be observing. I think he only made it appear that he is unqualified and transferred, but in reality, he is still in the school, watching, observing.
Another thing, when he stops time, it seems he has another ability, manipulation or convincing. Because after he stopped the time, the PE Teacher changed his tone; instead of convincing the student to stay, he just agreed.
Mr. Time Stop did something during that period he stopped the time. He changed the PE teacher's mind.
If only 1 parent is superhuman, the child is 50% superhuman. Ms. Self-healing doesn't have the physical strength of her father, that is also common with 100% superhumans. She only inherited her father's self-healing.
That means, Mr. Electric Bus Driver, also only acquired his father's electric powers but not the physical strength and speed, that's why he was easily defeated with his first encounter.
It also explains what they were talking about when they were looking down on the American hunter (in the early episodes), because the 100% superhumans understood the secret of being children, to be 100% superhuman descendant, both parents should be superhuman too, otherwise, they're 50% only.
Eventually it gets diluted.
It also appears that a descendant acquires the main ability of their parent, the first to be sacrified is physical strength and physical speed. Maybe, if they train well for years, they can gain a portion of their missing strength and speed.
The real question now is, how did superhumans started in the first place? From what the North Koreans hinted at, it was because of one South Korean that the NoKors started to develop their own superhuman program.
That implies, it's all about blood and genetics.
If so. Who was the first superhuman? And who spread the genes?
If he started to build his relationship with his granddaughter, he might start thinking to let everything go “for the sake of his granddaughter” and not achieve justice for his daughter's death.
That must be very hard for the grandfather. He had to keep her daughter's only child at arms length just to keep going with his investigation. The granddaughter who keeps reminding him of his daughter. The granddaughter who can make him happy because, in a way, his daughter lives in her.
But, he has to do it to keep his resolve, as well as to protect her and his other daughter.
That was a good background story for the grandfather. I like it.
And how they showed the grandfather cares so much about his granddaughter when she showed up with blood over her, also revealed how much he cares about her, and how he was just forcing himself to keep her at a distance. That moment, he was crushed.
Which was also no doubt the reason he turned his investigation over to the police. When he saw his granddaughter with blood over her (and probably ignored him as well), he realised he has no more time in the world and yet kept his own family away from him. That even though he cares so much about them, his investigation has consumed him and it cracked their relationship.
Great writing for me. It's not every day that you see something this deep as a background story for a support character. It's deep and meaningful. It makes us think, “would I make similar decisions if I am in a similar situation?”
Another thing is, I think the Americans were only targeting the old cohort, and have a different plan for the 2nd generation.
Another thing is, I think the Americans were only targeting the old cohort, and have a different plan for the 2nd generation.