I am aware, i am going to let it amass a bit, then read from the begining to get a refresher on it.

Ah, he meant like roided-out bodybuilder muscles.
Loyd's elves were bulkier.

if i had to posit a guess, witchcraft (the actual practice, not the assorted box of deviant religious practices)
Which craft has numerous rituals, everything from cleansing by using an egg to cursing someone to stub their toe more often.
The aforementioned rituals occasionally employ circles and/or runes to make things flow correctly.

Interestingly, witchcraft (at least as far as I know) has no concept of mana or something similar.
"Mana," the term, came from Hawaii. Mana was the life force or spiritual power one had when born.
It was something you were born with, and some were born with lots and others very little amounts.
You could increase your mana by killing other things, like during hunting or war.

Runes are what the Vikings/Norse used to... well, read and write; they were bits and pieces of their alphabet.
There are also other symbols from Buddhism, Christianity, Judaism, Islam, and even some symbols of hieroglyphics.

Now, to answer your question (sorry about the preamble; I'm just a little autistic about this topic and wanted to answer every aspect of your very broad question), the very roots of it come from witchcraft, Hawaiian folklore, the Norse alphabet, and miscellaneous symbols from various religions and writing systems.
Some symbols are more popular; others are rarer. Most of the time they copy a source and run from there, which is usually Dungeons and Dragons or Lord of the Rings, which often leads to similar symbols being common.

He probably won't need help until he encounters whatever is making the beastmen so bold. Because there has to be a reason these idiots are courting death.
Patric will then say, "Ah," then summon the devourer to "handle" the strong one, then continue his killing while the devourer and the mysterious one are "having a nice talk."

I wouldn't call him ignorant. There's the very real chance that he doesn't read manga like OPM and only stuck around that area of webcomics because "sick badass edgelord grows stronger" drew him in and he never had a reason to read other media here. I was at one point similar, only sticking to "Guy missing 90% of brain gets put into fantasy slop world and grows stronger." I just hope he picks up another book, as opposed to sticking to what is comfortable.

It was probably an OPM reference. That was a meme in their community before Solo Leveling got off the ground.
https://i.postimg.cc/14hQHCMB/i.webp

No heart rate = no erection
An odd quirk about the human body is That part's size is majorly affected by how good your heart is.

I assume that only works on weak people.
Yes, it's a power with horrific use cases and potential, but it looks like it needs delicate control, mana, and stationary/predictable targets.
Aside from that, I'm waiting for him to give people heart attacks by stopping their hearts from moving or generally fucking around with the nerves in people's bodies.

https://i.postimg.cc/bvdB4w0T/i.webp

It's not like she dies forever.
And she didn't say she was aiming specifically for the top 100, just that she wanted to keep up with him.
She is a textbook "rival" archetype, aka someone who uses other stronger people as a grindstone to get sharper.
Now, whether this is realistic is up for debate, but your lack of perception and fundamental misunderstanding means you haven't read many of these (or turned your brain off on most of them, which is fair).

I did not expect much.
I expected basic but reflavored isekai trash manga.
I got the worst writing I've seen in a while.
If I were to equate it to a food, it's like expecting stale bread and getting Styrofoam.

https://i.postimg.cc/cCtBHVCd/i.webp

Well, considering who around her is a bastard that is planning to remove her household, a certain prince comes to mind.
A prince known for their underhanded and aggressive tactics that would be motivated to remove those who could impede their tactics or had knowledge of their doings.

I wonder why I think of that silver rat...

Ah yes, the Geometry Dash heartbeat.

It's kind of like the WWE if the fighters in WWE actually fought, could avoid death, and fought other actors in D&D-style dungeon crawls.
Not my cup of tea, but it's less weird than the premise sounds.
4/10 considering the market.
6/10, ignoring market saturation.

It's good. Bookmark it.

I'm just going to dump my thoughts here. It's your problem now.
Who... Who is the intended audience for this?
They keep layering shit atop one another, and I'm stuck here thinking, "Why go through all these hoops?" and "What the hell is happening?"
Am I resistant to psychological thrillers to the point I feel fuck-all from this, or is this just shit?
A mummified corpse's worth of romance.
Maybe I just hate psychological dramas?

What is it with talented artists getting horrible injuries?
At this point, I'm starting to think artists have anti-plot armor.

"She felt dizzy and felt the ground thumping." Was her caught up in her emotions, attributing the thumping to her heart instead of a giant metal golem.

There is no Geneva Convention here.
It is "open season" in the war criminal sense.