Every city has a "city vein", which is an invisible energy network nourished by historical events since the city was founded, humanistic spirit, landmark buildings (such as century-old bell towers, ancient bridges, old churches) and even underground pipelines and subway tunnels.
The energy of the city's pulse is not perceptible to everyone. Only a few people are born with a "pulse sense", or they awaken the ability through contact with ancient objects (such as old maps, old clocks, and ancestral jewelry) that contain the reverberation of the city's pulse. The male protagonist's ability comes from this.
City vein energy can be divided into "active" and "inert": the city vein energy near the city center and popular landmarks is more active and suitable for martial arts practice; the city vein energy in old cities and abandoned factory areas is mostly inert and requires special methods to activate, and may hide "pulse barriers" (similar to energy traps).
