
I'm reading the novel and it explains in depth that the reason that there's an instant bond is because in that world they have a fated mate thing. When you exchange and mix your magic powers with someone you will know instantly if that person is your destined mate. It's similar to what imprinting was in the Twilight universe. The novels are better cause they explain and world build better than what a manga can do.

oh, ig what does his age means was his physical age but not his real age since he was a doctor in his rl, so its considered he is an adult. he also stated it there that he was a late bloomer. so like, he based his age there in his new world thru his physical appearance, perhaps? after all hes got a very small build like a child. even doug got furious as to what is physical age since its his first time hearing it. tho, these are jst my speculations
"15-16 year old adults" is a wild fucking sentence when you consider the fact that most 15-16 year olds just got out of middle school. I am all for world building, but there is no reason your world should consider 15-16 year olds ADULTS.
Officer, yes, these 2 men right here.