Like most MC's this one has eidict memory remembering a bunch of stuff that happened 20 years ago like it all happened yesterday.

MC is explained as having 20 years of battlefield experience which is why he is such a bad ass at tactics, military knowledge, troop management as well as having knowledge about everything.

However this is a setting on top of the fact that a) MC was a low ranked group leader never gaining a rank over leading 20ish people b) the MC didn't know how to read untill 5-10 years had passed on the battlefield c) most of his time is explained as having to earn money since he had to pay for gear and bribes and move to a higher tier army which is a big reason for his low rank since d) it's under the setting that secret, vital and dangerous information was freely handed out to every soldier in the armies (no fear of information leaks here eh?) e) While appearently having no money he was somehow while being a low ranked leader with no connections able to get information about most things, people, places etc etc.

So with those points and more the MC is many times better then an commanding officer with 10 years battle experience since he has 20 years he knows stuff and tactics not even people going through commanding officer training. He also for some reason got a hold and studied all his previous battles so that even when from when he was a newly arrived grunt he knows everything.

So if you can look past that he somehow managed to get a hold of, and read up about hundreds if not thousands of battles, tactics, events people, terrain etc etc that would have taken years while never leaving the battlefield except for short vacations. It's a good read.

The MC joins the army with a guy (I believe their from the same village as well but can't remember if it is so or not) who is extremly skilled at using the spear who was quickly acknowledged and specially chosen to be trained. This led to him becoming a master in the spear on a fast track in carrer and nobility eventually becoming a duke.

The MC pretty much downplays how he became distant and wasn't a "good" friend (this is the vibe I got) after becoming rich and famous. Even so the spear guy taught the MC his self created spear technique and that he named after himself. Which the MC then uses all the time, and through out the stories begining. He also helped the MC out by handing him some tips and information to help him out when he could, while also helping him financially from time to time. We also later find out the reason the MC could even reincarnate was that the guy used his most precious artifact said be able to bring someone back to life in the hope of brining his best friend (the MC) back to life which leads to the MC coming back to life but in the past.

So how does the MC thank him? By teaching him his future self created spear technique and shamelessly renaming the spear technique in his name and saying he was the one who created the spear technique. He also makes the guy his subordinate and steals his fast track carrer opportunity cause the MC is N1.

So yeah douche detected

(slightly tsundere) Potential water spirit king candidate following the dude. Not annoyingly though. Oh, and the reason for his time-travel was mentioned vaguely. I hope MC finds out all the details.

The seemingly main girl is nice and all, but the reason for Roan and her to fall in love is kinda meh. It's fate???? What the... At least they don't immediately decide that they're in love and swoon together, but still. Their romance is interesting though.