The connections between Shadow and Ryuko are that they are both black and red anti-heroes with short tempers and aggressive personalities. Both are half-alien, having been genetically engineered and fused with alien DNA (Black Arms and Life Fibers, respectively) since their creation/birth, and are also the biological off-springs of the main antagonists of their story (Black Doom and Ragyo Kiryuin, respectively). Both sought vengeance for a loved one (Maria Robotnik and Isshin Matoi, respectively) and were initially enemies to a blue colored rival with a similar power-set (Sonic the Hedgehog and Satsuki Kiryuin, respectively) before eventually teaming up with them. Both also receive increased powers via extraordinary sources (the Chaos Emeralds and Senketsu, respectively), which can give them a golden, glowing super form (Super Shadow and Senketsu Kisaragi, respectively), with the climaxes of their stories involving them falling from space after a final battle in the aforementioned golden super form.