Liu Yiwu is a Chinese officer serving in Annex I and the leader of the Sino-Asian Squad number four after their crash landing on Mars. He is a very tall man with black hair, black eyes, a large beard, and glasses. Born in a less affluent area, Liu entered military service after graduating at the top of his college class through hard work and personal connections. At age twenty-four, he married the daughter of a high-ranking official, and his diligent army career led to his selection for the Annex Project. His personal interests include keep terrariums and raising coelacanths, and he enjoys very spicy or strong food while disliking keyboards with small enter keys. He also practices kenpo as a skill.

Liu is loyal to China’s national interests above the mission’s stated goals. He is calculating and deceptive, initially allowing others to believe he and his squad were killed when their burned corpses were discovered. This was a deliberate ruse to seize control of the Annex I spacecraft and ultimately position China as the dominant global superpower on Earth. He later reveals his true intentions by demanding that Shoukichi Komachi hand over Akari Hizamaru and Michelle K. Davis so China can study their natural abilities, indicating a strategic motivation to replicate those powers for national advantage.

Despite holding a low M.A.R.S. ranking of forty-four, that rank was deliberately falsified so he could be placed in the engineering division while the officer positions were already predetermined. According to the Mars File guidebook, if he had been ranked seriously he would have been number four, placing him among the strongest members of the Annex I crew. His M.O. operation granted him the powers of the blue-ringed octopus, which enhances his strength and durability considerably. He can generate tentacles from his body, use them to restrain powerful opponents like Komachi, and produce a potent tetrodotoxin that causes paralysis. He also exhibits a degree of body regeneration, allowing him to recover from heavy hits. Like all Chinese members of the expedition, he concealed his true combat ranking.

Liu’s role in the story is that of a covert antagonist who initially appears to be a fellow crew member cooperating in the fight against the Terraformars. However, his true allegiance lies with China’s government, and he works to undermine the multinational effort for national supremacy. He engages in combat with Komachi, revealing that he had lied about his claimed anaconda abilities—his actual powers are designed to be anti-human rather than anti-Terraformar. He later fights Sylvester Asimov before escaping back into the Annex. His development shows a pragmatic, ambitious soldier who uses deception and nationalistic fervor to pursue political dominance, making him a complex threat not just from the mutated cockroaches but from within the human expedition itself.