Seelkadoom has the personality combined of Sonic and Shadow, only evil and more destructive. He also appears to have his own personality, likely because of his negative Chaos Energy side. Like Sonic, he taunts his opponents and mocks about their strength and speed, representing Sonic's cockiness. He also appears to be very arrogant and aggressive, very similar to Shadow, only much more violent. He also doesn't seem to be afraid of anything, even though his opponent is stronger than him.