Izuku Midoriya: is caring, emotional, selfless, strong-willed, smart, analytical, polite, empathetic, kind, determined and diligent.
Katsuki Bakugou: Bakugou is arrogant, short-tempered, snarky, aggressive, prideful, competitive, strong willed, brave, irritable, driven.

Midoriya only calls Bakugou "Kaachan" and Bakugou only calls Izuku "Deku".
They are both teenagers, students of Class 1-A, at UA-highschool training to become pro heroes. Izuku and Bakugou are rivals!