Imagine that you were born very sick.
Imagine that you were born from an artificial surrogate womb, because your mother was also sick. Mother would've died if she bore you, so she and Father petitioned a Ruling Sister for your conception. Your parents were sterile, so you (like more and more) were a clone of your parents. Your Mother died young anyways; she was a good fighter, but she knew she couldn't fight illness forever. She died with a smile. Father followed her, as he did everywhere else.
Imagine what it's like, to have to live in a suit. This softsuit is not for life support; it's to bolster spindly limbs, fingers that have trouble gripping, toes you can't balance on. The suit is like an exoskeleton, while the real life support is the network of implants you need for your organs to function. The surgeries were frequent, but the suit's more in your mind because there are times when you are without it. When you must change, you're so weak you need an assistant to help you put on the new suit. It makes you clench and unclench your fists, remembering how limited you can be.
Imagine what it's like, to know that this is normal. More and more people are being born sick, and you want to know why. So, you learn about mutations, from pollution and cosmic rays; you learn about telomeres and abnormal genetic expressions. You learn how it works, and you want to learn how you can make people not like you.
Imagine what it would've been like, to be an Orokin. Tall, broad, healthy, growing old slowly and gracefully. You need to know how they altered themselves, so you need to spend long hours chasing every scrap you can find. You study the equivalent of Orokin graffiti and rummage through their trinkets for any clue on how to rewrite genes, to recreate people like they did. And most of what you find is nothing, so you look for many years.
Imagine that you are very sick, and old, and tired. You looked for scraps, and now scraps have found you; weapons forged in the shape of man, masters of blade and gun. They are going to kill you, because that will hurt your people. Even if you are a good fighter, you can't fight them forever. So, you hide what information you can, you pick up the ceramic sword you studied along with the trinkets, and you die with a joke.
Please, imagine this, and remember what Tyl Regor did for his people. Remember that he fought as long as he could for as much as he could, and that he died with acceptance. This is how you understand him.
-Elegy, attributed to Ruling Sister Regor.
Author's Note
Even if the Grineer and Corpus are supposed to be unreasonable and hostile cultures that are trying to exploit Orokin and Tenno technology, the Tenno are a bunch of weird one-person armies that woke up from what are basically ancient space ruins and started mutely ripping things apart for their BFF Lotus. They slam into military space in cells that are composed of up to four warframes, and then kill dozens of people for money, resources, and modules to charge up their gear. Also, one of their missions is to kill a Grineer researcher to prevent genetic therapies.
So, with a little push here and there, you could reinterpret the setting and go for a flipped tone where the remnants of humanity (and crazed Infested) struggle against the overwhelming destructiveness of the Tenno and Orokin technology. I hope to write more chapters soon on different characters, but this will be my corny start for now; the future will have better story-to-author's-note ratios.