These three characters are Axel Mode-exclusive, but can be recruited in the Land of Carnage during the Main Story AFTER clearing Axel Mode. You must be able to recruit Axel in the Lad of Carnage in order to recruit these three. There are even more recruitable characters. See the "New Features" section in the main article for more details.
Saber Pink was originally a member of the Evil Rangers. However, she joins Axel as his sidekick during his travels. Saber Pink will join Axel at the start of Axel Mode. She is a recolor of the Saber Kitty Monster class, and should be treated as such. She is also the tutor for the game's new battle mechanics.
The Actress joins at the end of episode 2 of Axel Mode. She is a recolor of the Wyrm class and should be treated as such.
Main Hero B
Main Hero B is a masochistic angel that was present in the dinner theater Axel fought his way out of. She joins him in order to gain new oppurtunities for punishment. She is a recolor of the Clestial Host class, and should be treated as such.