Given the high demand for material and manufacturing technology, internal combustion engines came several decades after the electric motors in the previous world where Roland had lived.
Fantasy · Er Mu
Part of the reasons why he didn't dare to use his full strength was because the other party was Yang shi's direct disciple, but more importantly than that, if he were to devote his full strength to executing the Sea Severing Sword, he would have to expend all of his zhenqi before the sword art could be stopped... It was one thing when his zhenqi capacity was still lower, but after the alteration he had made to his dantian through the Dongxu Gourd, the amount of zhenqi he had in his dantian rose to fivefold of what it previously had. If he were to lose control of the sword art once more, a huge problem could very well occur.
Eastern Fantasy · Heng Sao Tian Ya