Other: Concept theme
Part of the theme of the Buffyverse is that power is bought or given at the cost of your humanity. We see throughout the show that Buffy laments her lack of a human life, she wishes almost constantly to just be a normal girl but can't be. A slayer is essentially part demon, gifted with supernatural strength but also cursed with prophetic dreams of evil and a destiny to battle it which will always bring her and the forces of darkness together. We see her calling mess up her real life over and over, at times rendering her homeless, getting her expelled, costing her normal relationships or a non minimum wage job. We see again in Willow, a character who begins as very human and very happy. But who as she practices magic and becomes more powerful has that power consume her life. Destroy her relationship, cost her the trust of her friends, and even her own willpower and sanity.
It is even more pronounced in Angel, where we see him as someone who yearns for a normal life, to just be able to go out into the sun, to be with his true love or enjoy the taste of ice cream. But he cannot, when he is given this, he is overjoyed and could not be happier. That is until he realises that it's come at the cost of his ability to fight, that he cannot have both. And so in the end he gives it back.
In our game this trade off is represented with concepts, as you progress up the concept chart the archetypes become less and less human. A human would struggle to make it into the 40s, they could make it there if they have years of training or experience, advanced weaponry etc. But even then they'd be giving up some of their humanity to achieve it, a level of dedication is required that costs much of their human life. This is best typified in the journey of Wesley, who we see in Angel progress to a 40s concept character when his throat is cut and he is abandoned by the people he cares about. He becomes consequently more jaded, and cynical, a colder and unhappier man. But also for it a more capable demon hunter, with a cool expanding sword.
While those in their 40s could probably return to a human life, for those in their 50s it's impossible. At this point they are not entirely human any more, part machine or monster or magic. It's difficult to go be your every day business man with a robot arm or a magic addiction, no matter how much you might want it. And if they move into 60s they're now more their power than they are human, they wouldn't recognise a human life enough to know they should want it, this is why so few heroes are ever this powerful. Because they've lost touch with humanity too much to
care about fighting for it.
This is the poetry of the world, but also the tragedy. The heroes of the Buffyverse give up their humanity so that the ordinary people can enjoy theirs, can have the privilege of being normal, human and weak.
It may be tempting at times to try to milk the most you can out of your concepts, or even come up with modifiers and the like that you can argue technically fulfil some criteria even while having no effect on the actual character. I mean if you can have the best of both worlds, why not? Isn't it everyone's fantasy to be some person who has a good and happy human life, while also being able to pull the heads off Turok'hans? But in the end you will just make that power meaningless and hollow, and the character themselves not a real person, but rather little more than a combat
See Also: concepts