The Orb Boss, who in game is named Orb Holder Yoshikage, is a neon red reskin of Yoshikage Kira. However unlike Kira, it only uses a barrage and a roll. It has a impressive 796,000 HP which is the same as normal Kira's. He does the most damage any boss does in the entire game yet. The Orb Boss is also the only known way to get the Shiny Red Orb item, it is unknown what this item does but the drop rates for it are very low. Estimated to be 1% or less (the shiny red orb has not been confirmed by anyone yet including the devs, so there is no proof as of now). This Boss also drops many of the in game orbs, including the Shadow Orb, Flushed Orb, Cracked Galaxy Orb etc. In order to fight this boss you must talk to the Mysterious Orb NPC, after the dialogue is over it takes up to 15 seconds to be teleported to the Orb Boss Arena, which is filled with neon red skulls, candle towers and a massive throne at the end. Also if you look up at the ceiling, it has what appears to be glowing red neon eyes.
(Also if the red orb is real, Then the chances of it dropping are VERY LESS>0.1%?)