A lighter, more action-oriented series often categorized as "Real-Trash-RPG" by its readers.
3. Yuri Vinokurov — Eternal War: Space Marine (LitRPG/Action)
This is a seminal 1974 novel inspired by the author's combat experience in the Vietnam War.
: It follows William Mandella, a soldier fighting an interstellar war against an alien race called Taurans. Due to time dilation from near-light-speed travel, Mandella ages only a few years while centuries pass on Earth.
2. Sergey Karelin — Eternal War (Contemporary Russian Fantasy)