• Custom Robo
• This is the Ray Mk III. ItÂ’s the same type that appeared in the Nintendo DS title Custom Robo Arena.
• When summoned, the Ray Mk III whizzes around in the air, alternately firing off a shower of bullets from the gun on its left hand and peppering the stage with bombs from its right.
• Since itÂ’s a toy, the design for Ray Mk III is small and lightweight.
• Isaac
• Isaac is an adept from the Golden Sun series who commands earth-based Psynergy.
  
• He carries a sword on his back but you wonÂ’t see him use it here.
• Isaac has the ability Move, which has the ability to move objects. This time, that ability has been represented as a massive hand that pushes away anything in itÂ’s path.
• Infantry and Tanks
• These famous units from the Advance Wars series have been represented in Smash Bros. as pixel art.
  
• Looking at the number of colors used, IÂ’d say these are the units as they appeared in the Game Boy Advance version, perhaps?
• Both types of unit spill out onto the battlefield firing tiny projectiles as they wheel about.
  
• They may be adorable, but you mustnÂ’t underestimate them.
• Barbara
• Barbara comes to Smash from the game Daigassou! Band Brothers and Master of Illusion.
  
• SheÂ’s also made appearances secretly in games like English Training.
• When Barbara appears, she starts to wail on her electric guitar, attacking opponents in the area with sonic waves.
  
• The attack can cause multiple hits, so run when you see it coming!
• Shadow the Hedgehog
• Shadow The Hedgehog joins the brawl alongside Sonic!
  
• Shadow is known as a sort of rival for Sonic.
• When summoned, Shadow uses his Chaos Control to slow the speed of those nearby him.
  
• Naturally the Chaos Control has no effect on the character who summoned him.

Via Smash Bros. DOJO!