The seahorse's tail is renowned for its exceptional bending ability and strength owing to its unique biological structures. Inspired by this, this letter presents a novel modular cable-driven continuum robot with remarkable load capacity. By employing an asymmetric structure with both flexible and rigid connections in different directions, the proposed robot adaptively grasps objects of various sizes and shapes while handling substantial loads. To study the impact of cable length variations on the robot's motion, an equivalent model is developed to derive the robot's forward kinematics under ideal conditions, which is subsequently validated through experimental analysis. Moreover, stiffness analysis is executed to clarify the structural stability in different directions. Experiment results show that the proposed robot can grasp objects sized from 60 mm to 250 mm and a maximum weight of 3500 g. In summary, the robot exhibits remarkable resilience against impact loads, which is suitable for robust grasping of non-cooperative objects.