i just finished and i looked it up and apparently nothing. there is nothing to do. kinda sad.
you can't
Gehtis disappeared. You cannot find him anywhere unlike the other sages.
At black city but it's hidden somewhere therE
Sorry, but N disappears after you battle him and Ghestis in the Pokemon League.
after you catch the six savage pokemon you have to find all seven sages
go to www.pokemon Black & White-New pokemon.com to find out.
He pops up out of no where and tells you news about N then leaves.
Well you defeat alder and he will register your pokemon on the hall of fame. After that you have to find all seven sages including ghetsis.
he only is in Pokemon platinum and Pokemon black and white in Pokemon platinum you see him in jubilife city, and I think maybe at Team Galactic HQ. in Pokemon black and white after you beat the elite four, he is looking for the seven sages. after you find all seven sages he'll talk to you and he'll arrest the 7 sages. you will never see him again after that.
look for n
catch "em all
you have to search all over unova to find them. 5 of them are in the first half and 1 of them is in the 2nd half. You will figure out what to do after you find the first 6!