Star-D is one of four main members of the now disbanded Star-Force. He is equal in power to Star-C once he started training. He, along with Star-A are now dead because of Viaton in Season 4.
A member of the eight wish gods known as the Star Force, he was bored with simply granting wishes. Seventy-Five came to them and convinced him to defect and become evil, however, this was shortly resolved upon dealing with Daurel with Star-D. Later he and the Star Force gave up their wishing power along with the Soul Warriors to weaken Xamo.
80 years later Star-D has trained and unlocked his Ancient form, coming in to aid the heroes after the revived Seventy-Five fled. Almost instantly killing Hecon, Squinian, and Pops without mercy. Then he teamed up with the other three Star Force members to fuse into Star-X and fight Seventy-Five. Even with the help of Star-K and Bomcol, he overpowered them and they fled.
He and Star-D travelled with the heroes to assist them, fusing into Star-X whenever needed, such as Vileon, Universia, Comelos, Jupitais. Unlocking his Ancient Level 2 form against the final one just in the nick of time. Continuing on and training for 19 years for the fight against Omniscience, going to Universe 6 and fusing to fight Phenteyegor and finally Alpha Viaton.
Viaton blasting Star-X in half, ending Star-D's life...
Star-D was heavily influenced by Bill Cipher, being a yellow shape with one eye and black lines for limbs, and a hat. The similarities end there, Star-D being some undefined shape resembling a heart, his arms much longer than his legs, and his head resembling a bowler cap with a wide brim. Strange lines go across his body that seems to have no particular pattern besides the rectangles on his left side.
His transformation gives him a dark cloud-like gradient, while his second transformation shifts his colours to grey with a fire gradient over it, his eye turning red with a white pupil.