First, let me just say, well fucking done. The fact that you did both the art and writing is nothing short of impressive. Your artstyle is awesome, and even though you say writing comes second, it is still excellent. It's rich and detailed, really putting the reader into the story and engaging with the characters. At no point does All in Love and War feel boring or tedious.
I won't deny, after reading Hardy's death, I was pretty upset, lol. You did an amazing job of writing him, and he feels very real. He's the kind of guy I'd want to just hold in my arms and comfort, with all the shit he's been through. Everything after the final date is an emotional gut punch, raw, and impactful, and tbh, I fuck with that kind of writing energy. Honestly, I felt way more sad that Hardy had to lose Jayden in his death, than I did with Jayden losing him. Hardy's the kinda character where you want nothing more than for him to finally be happy and content in his life, being truly loved by someone, and that not being allowed to happen...man, that hurts.
After reading your reasoning and explanation for why Hardy had to die, I can't say I disagree. The only thing I'd say I disagree with is how Hardy died, not that he had to. If I were to write it, I would have had him be diagnosed with a terminal illness, and told Jayden about it. I would have them both leave the Marines and let them have a few months of happiness together before death took him. Everything afterward, Jayden reading his last words, becoming a professor, all of that I'd leave the same. Actually, that's the way I thought it was going to play out, when Hardy kept dodging around why he was sad on the second-to-last date.
But then, when he reveals he's getting transferred out, it's heart-breaking. But there's a glimmer of hope that he and Jayden will be together again someday. Then that's ripped away with him being killed in the line of duty. As a reader, I'd say that was my biggest issue. I hate getting teased with a positive outcome, only to have it stolen.
Moving onto Jayden, I again think that you did a really good job of writing him and making him compelling. Actually, I would say that I identified with Jayden a lot. His early woodenness, penchant for academics, and hesitancy all felt really relatable to me. I was hoping that it'd be revealed in the epilogue that he had found another man and was in love with him, to really solidify that he had moved on from Hardy, but that wasn't the case. Unless that's in the cards for a future work?
As for Ahmed, I think he was the least fleshed out of the characters. I didn't really feel strongly about him one way or the other, even after the reveal that Hardy was his step-father. I just don't think there was enough time to really develop him. I look forward to seeing what you do with him in your next project though!
Final thoughts. For your first project, it is really well done, and as a fellow writer, you definitely have my respect. Hell, if I ever do a VN project, you'll probably be one of the first people I reach out to for art, because your artstyle is really fucking good, dude! I honestly think you have a lot of talent, and I wouldn't be surprised to see you become a more well-known name like DyneWulf or Braford. Can't wait to see your future works!