When Tomohiko Taniguchi learned that former Japanese PM Shinzo Abe had been killed, he felt many things, but first his thoughts turned to the man who took the life of his ex-boss and mentor.

"I was filled with a lot of but different emotions all at the same time," he tells Ian Bremmer on GZERO World. "Disbelief, grief, [but] the strongest emotion, of course, was anger."