The protagonist, Cheon Yeo-Woon, gets a suite of abilities from the implanted 'Nano Machine' that go way beyond just physical enhancement, though that's the flashy part. It directly interfaces with his nervous system, allowing real-time combat analysis, instant learning of martial arts by copying movements, and even predictive simulations of fights. It can also repair his body from severe injuries, regulate his internal energy, and has a database of lost or forbidden techniques. The initial power-up feels almost cheat-like, letting him crush early opponents, but the story gets interesting when stronger enemies and the machine's own limitations/upgrade requirements force him to keep evolving. I like that it's not just a passive stat boost; he has to actively command it and integrate its functions with his own growing skills.
What stuck with me more than the super-strength or speed was the 'Nano Domain' ability. It lets him project a field where he can control the nanobots to manipulate matter at a microscopic level, which gets wild later on—disassembling weapons, analyzing poisons, that sort of thing. The power creep is handled decently because the world's martial arts system is also full of OP stuff, so the nano machine feels like his unique path rather than an 'I win' button. Later arcs introduce the machine's origins, which ties into a bigger sci-fi mystery amidst the murim setting.