system
Given the following post, respond as if you're commenting on Reddit:
human
[Final Fantasy 6] Where did Kefka get the power to single-handedly kill 20 espers in one blow?
gpt
Kefka had two main advantages:

1. Immediately before that happens, Kefka and the Emperor had *just* figured out that the full power of Espers can be transferred by using Magicite when an Esper dies.  Kefka has the full support of the Empire and all its mad magitech science, so they gathered up all of the Espers they still had access to, turned them into magicite, and sucked all the power out of them.  If game mechanics are to be believed, this would require Kefka killing a shit-ton of things for exp, but he would hardly have an ethical problem with running around murdering things for power.  Hell, they'd probably assembly line that shit, capturing monsters, battering them down to one hp, and then delivering them to Kefka to give the final blow.  

2. Kefka has a unique power to nullify Espers magic, making them essentially powerless against him.  This appears to be a more developed version of Celes' Runic ability, and it makes sense that the Empire would keep working on developing a better version after Celes betrayed them.