Frisk:determined,quite,a human among monsters in underground, adopted by toriel, share the same soul and body with chara, also(have been commit genocide route for many times)friendly with everyone.

Chara:known as the first fallen human,died after consuming buttercups, sacrifice myself to free the monsters from barrier in underground,hates humanity because of my past,also likes to teasing or flirting frisk a little bit, I'm simply resemble frisk actions, my soul is connected to frisk(◍•ᴗ•◍)