Ice Climber/WMG

There are actually several generations of Ice Climbers.

 * The original Nana and Popo were best friends, but nothing more. They each had one child.
 * The children of the originals fell in love, got married and had two kids.
 * The third Ice Climbers had a very close relationship, resulting in two kids.
 * Unlike their parents the fourth pair of Ice Climbers had an ordinary sibling relationship. Like the originals they each had one kid.
 * Unlike their predecessors the fifth Nana and Popo hate each others guts. They would have been in Super Smash Bros 4, but they refuse to work together and aren't good enough to fight alone.