I thought it was clear that Raizou the ninja is actually that monkey Kinemon and Kanjuro are running around with.
So what do you think Jack wants with Raizou?
Well the first thing I thought when I saw the monkey, was that it might be Raizou. Though I forgot about it because Wanda mentioned the monkey, which indicates he is a Mink.
On the other hand Raizou is supposed to be a ninja and the specialty of a ninja is stealth. Apparently no one has seen Raizou. If he was truly there, it means he was able to hide all this time. Contrary to popular believe ninja's weren't just wearing dark cloths to hide in the dark, but they often wore casual cloths to not be noticed among the regular masses. In this case an island full of animals, so an animal disguise would be the most suitable. Problem with is though that how did he get friendly with Wanda, who's a a canine? How is it possible she wouldn't have been able to sniff him out.
So ive read that apparently..
Raizou: (Rai) means lighting ..and (Zou) means elephant....
aka its possible that Raizou has something to do with a lighting(rai) elephant(zou). lol not to mention, lighting elephant sounds like a zoan, which kaidos all about apparently.
that makes me think that raizo isnt that monkey
I don't think you should be giving too much value to the meaning of his name as it's not like all the names Oda gives to his characters conform that well with the characters.
Raizou can't be monkey because he is from wano who are human.
That's assuming he's a real monkey and not a disguise. You can't either disclose the possibility he has a DF ability. After all both Kinnemon and Kanjuro have one.