Monster Hunter Tri was created on 2009-08-01.
Monster Hunter Freedom was created on 2005-12-01.
Monster Hunter Frontier was created on 2007-06-21.
Monster Hunter Dynamic Hunting was created on 2011-06-01.
Monster Hunter Freedom Unite was created on 2008-03-27.
monster hunter wiki
that would be Monster Hunter Freedom Unite on PSP and Monster Hunter Tri on Wii.
No one in the world can sensibly be a monster hunter as monsters aren't real. However, there is a video game called 'Monster Hunter' and it is popular and one can become a monster hunter through there.
I will answer any monster hunter questions you have :)
You can get that and more on the monster hunter wiki
There is no way to get invincibility in Monster Hunter Freedom.
Monster Hunter Tri happened in 2009.