Unlike other reincarnation novels, the MC of this one is 23 years old when the story starts. He has a very realistic view of romance, considering he already lived passed his 40s in his previous life, so don't expect loli heroines that ruin so many other reincarnation stories.
The first 30 chapters are mostly flashbacks of the 'past 10 years' since her reincarnated, and overly wordy setting descriptions. You have to give him credit for the flashbacks though, showing a heart wrenching romance, his life, as a student then teacher, and introductions to his goofy mercenary and other buddies who he gathers with at the local tavern. The "plot" only really begins around chapter 40.
And seriously - the author writes an arc about him getting a secretary pretty much just so he f**ks her whenever he wants, or as the author summarised himself: "when there's work, he gives it to the secretary to do, when there's nothing, he does the secretary" (I quote.)
And it doesn't end there, whether it's being raped by barbarian women because they are in heat because of his big pe**s (yes, the author likes to talk about that) or the three sisters who fall into his bed, and many more... possibly not impossible, but totally author's fantasy moments, these all detract from the otherwise gritty features of the novel.
a) M*gic the gathering: One of his abilities is from the card game system of OP magic that nobody else has any clue exists and yet where cards appear all over the place in people's pocket's and out of thin air. I think it's a great concept... for a novel that actually focuses on that. As a system of magic, it just has no relation to the setting, other characters or the mythology (yeah, he tries to create deep hidden conspiracy theory type explanations, but it's pretty lame).
My biggest issue of all is that he could have done everything the cards do without the card system.
b) Ring of the ancients: so yeah, it's great you got an heirloom from your grandfather, it's great it gives you a magic spell, some stats and I'm even fine with it having a backstory and ancient spirits with sword skillz. Why did the author have to make it materialise an ancient spirit that wasn't even supposed to be in the item...? If you're going to make an OP item for your MC, don't make it more OP than it would normally be just to make your readers facepalm please.
c) Lionheart sword evolves into Gigasword: Again, he puts a neat backstory to an item, makes a nice scene where he gets the approval of some ancient king who wielded it... then a few chapters later decides it wasn't good enough, so he says it's only 1/4 of the sword that was actually an even better sword that belonged to an even more ancient king. Now he'll be 10 times more powerful!
Some of these images include his disguises: a highland knight and then later on as a Viscount from the South of Ailuin, his NPC identity as related to his grandfather, some of the other misunderstandings are even more interesting: as a dragon when the dragon loli helps him out with Makalov, him being a sun knight when he uses charge or the misunderstandings as him being the Dragon of Darkness by the witch and later undeads.