Hmm, let's see here:
Cover doesn't set up a lot of promise. It's hard to read, with low contrast on the text and a drawing that doesn't tell me a lot about what to expect. It'd definitely perform better on Tapas if the cover had characters on it and stronger contrast, because covers are displayed quite small, and without blurbs or even titles, so you need to make sure the cover has a readable title and really says a lot about the story or core selling points, like appealing characters.
Blurb sounds a little generic, and puts kind of unessential setting detail above the protagonist and story. Put the fact that it's a story about a protagonist seeking revenge against the gods first. You can tell me about the five warring nations later.
Immediate nitpick: This comic is tagged #isekai ....when it's...not? It's not an isekai This character is born and grows up in a Fantasy world. He's not from our world, or if he is, he clearly has no memory of it, which is one of the defining tropes of an isekai.
It opens with my personal pet hate of narration about backstory with stylised drawings not representative of the actual in-comic artwork, but thankfully they're not bad drawings in this one, and it doesn't last too long.
So... then we're in a sort of Japanese-looking village, with decent art. And... some guys praying to a Buddha statue they're calling a "Daimyo" (basically equivalent to a Baron, making this a weird thing to address a buddha as, hasn't he risen above being a daimyo now and become a butsu or a kami?) and.... then we see a picture leaning against a gong and it's.... Shogun Miyamoto Musashi!!? I... I wha-
Okay, time out.
Miyamoto Musashi was a real person (who was not a Shogun). His lifetime overlapped with William Shakespeare's. Can you imagine, if in this Fantasy story, we'd panned down to a village and there'd been a plaque saying "In memory of Captain William Shakespeare, Master of Fire Magic". That would be really jarring, right? Because William Shakespeare was a real guy, and we all know he wasn't a captain and he didn't do fire magic, so the reader would be like "Oh crap, is this a parallel universe, woah, that's wild..." But then we continue like nothing happened. It's like those bits in FF15 where it turns out Cup Ramen and Vivian Westwood exist in this fantasy world, and all you can do is go "I'm sorry...WHAT?"
There is a concept in writing called "Checkov's Gun" where "if you hang a gun on the wall, it needs to go off by the end of the play." If you direct my attention, as the reader, to Shogun Miyamoto Musashi, that's grabbing my attention. You should only show me something that attention grabbing as "holy crap, this guy who existed in our world existed in this world too!?" because you're going to pay it off. You can't establish that and then immediately just stop talking about it and take our protagonist off to be a Viking slave who fights in a Roman style gladiatorial coliseum. Don't set things up that you don't intend to pay off. Don't direct your audience's attention to things if they're not useful information, especially on your very first page!
It probably would have been better to use these early panels to set up the relationship between the protagonist and his beloved father who is a cool samurai the whole village looks up to, or to establish the tension between the village and their lord, or even that viking raiders have been seen in the area and they're kidnapping children from nearby villages... because these are things that come up out of nowhere later. It's good practice to set things up before paying them off.
So... the art is decently drawn, but very inconsistent. Anything isn't a character or held by one is just a 3D model (often in mismatched styles) or a cheap texture brush, and the art style varies wildly from character to character, or even from panel to panel, as if everything's been referenced from different comics, and whenever there wasn't a reference available, everyone's proportions go a bit floppy and indistinct. There's often a disconnect between the action or emotion in a scene and how it's drawn, because the drawings don't flow into each other naturally, it's like looking at a string of well-done recreations of generic manga or comics panels that depicted something close to what's happening rather than like an artist sat down and thought about how to construct a series of panels that give a sense of continuation of motion or mood.
The story is competently written, but not fun. From pretty much the second chapter on, it's just following the protagonist through misery after misery... and it forgets before that to really establish why we should like or care about him, leaning very heavily on him being a child and an underdog to make the audience sympathise. A big problem I have with this protagonist is that he's very passive; it tends to feel like stuff is happening to him rather than him making decisions. His village gets destroyed, his sister dies, he gets captured, he gets made a gladiator, he gets taken on by a viking guy... The only real thing he makes a decision about is choosing to end his own life, but he then changes his mind and doesn't, and I guess sharing some of his food with a slave and befriending her, which is the first thing he really does that feels like him making an interesting character-based choice that could potentially help or hinder him later... But then it's undermined because we turn the page and oop, well, she's dead now, again out of his control, and it backfills that they had become super-good friends, but it doesn't matter, because we're just being told rather than spending any amount of time following his training and growing friendship with her. She's immediately fridged (a comics term for when a female character is killed to further the motivation and growth of a male character. Also wow, his sister also got fridged, huh... So... is a female character going to get to survive long enough to have agency in this comic, or...?).
I think overall this story could have used a second draft. Once the story was written out and you knew what was actually going to happen, it might have been good to then go back and to rewrite it so that early pages set up key characters and story concepts that will actually be important (the gods really aren't, but things like his relationships really are). More world-building probably would have been good too. Like, one of the nations appears to be just... Japan, and then it's next door to a country that has viking raiders...who have Roman style coliseums... and wear Victorian monocles and flat peaked hats sometimes...and electric slave collars!? I have absolutely no idea what magic can do or what the tech level is here, and like the plot, it feels like everything's being made up as it goes along, when there really wasn't a need for that; this is a comic made by two people, so it must surely have been written as a script and then drawn, so could have had a bit more development time on the story before the drawing started.
There's promise in the polished presentation and execution, but I feel like there are a number of areas that could do with improvement here, some as simple as a new cover and blurb, but others are deeper story and worldbuilding issues.