“If Kamsa was so empowered why did he not try to kill Krsna himself? Why did he send others to try and watch them all lose their lives?” It’s part of the transcendental drama. That’s also the tradition in administrative warriorship. The king would send some of his associates to do some ‘jobs.’ If it’s tough, he would go to deal with himself. Krishna appeared to kill demons, not only Kamsa, mark you; and those associates of Kamsa are also worthy of annihilation. 🙂 So, that was part of the whole design.