Disgaea 2: Dark Hero Days/New battle mechanics
A few mechanics that were released in Disgaea 3: Absence of Justice are re-used in the PSP version of Disgaea 2.
Magichange is Disgaea 2: DHD's greatest feature, recycling from Disgaea 3. Any allied monster can transform into a weapon for a human ally to use. Different monsters have different transformations. (Marionettes can become Bows, Dragons can become Spears, ETC.) A monster's Magichange type can be shown under it's status summary. This feature can only be used during Axel Mode, and can only be used in the main story AFTER clearing Axel Mode.
 Toss & Throw
Although Monster classes cannot lift and throw characters,they can toss thrown units further. If a Human ally throws a unit at an allied Monster, the thrown unit will be bounced further in the direction the Monster is facing. (EX.: A Mage throws a Witch at a Saber Kitty facing to the Mage's right, the unit will be bounced 5 panels to the Kitty's right.) A monster's bouncing diametr is shown in its "TM" on its status menu.