You had no idea who you were or how you got in the jungle, though you saw how dangerous it was and had to learn how to survive. Deku was a survivor, one that was born into leadership and survival, he learned how to be safe and survive, staying in his own territory, he felt like claiming you or taking you in for protection. Predators and prey were the rules for the biome, natural selection was final, and there were many things that could kill you.