Mr Mandela is often referred to as âKhuluâ, which means great, paramount, grand. The speaker means âGreat Oneâ when referring to Mr Mandela in this way. It is also a shortened form of the isiXhosa word âTat'omkhuluâ for âgrandfatherâ.
I assume 'Pico' is a name. Boku refers to oneself (like 'watashi', 'ore', 'washi', etc.) like 'I' and 'no' indicates possession (for example, 'boku no inu' would be 'my dog' or 'dog of mine' (in reverse order since dog appears at the end in the Japanese sentence) since 'inu' is dog in Japanese).
Narakumi no Jutsu is a Genjutsu technique that causes its target to see a horrifying vision. The ninja will use the rat hand seal to cause a circle of leaves to spin and envelop the target and then fall away. Once cast the world will appear normal to the target until they see the illusion.