Horada

Horada (法螺田, Horada) is a prolific member of the Blue Squares and later the Yellow Scarves. He is a crude and brash individual who fears Shizuo Heiwajima, Kinnosuke Kuzuhara and Ran Izumii.

He is the main antagonist of the Yellow Scarves Arc.

Background
Horada worked under Izumii in the Blue Squares. He was one of the members who had kidnapped Saki Mikajima before the gang's first disbandment. After the Blue Squares' disbandment, Horada and other former members join the Yellow Scarves.

Saika Arc (anime)\Yellow Scarves Arc (manga)
Horada is first seen picking on Shingen Kishitani along with Higa and his other friends upon Shingen's arrival in Ikebukuro. Horada provokes Celty Sturluson after Shingen reveals that she had been watching, and she frightens the group of delinquents away. He and his goons attempt to fight Celty, but they are beaten up by Shizuo.

Yellow Scarves Arc
After serving under Masaomi Kida for a while, he takes over the Yellow Scarves and has any members loyal to Masaomi ambushed, blaming the attacks on the Dollars. He then shoots Shizuo and frames Masaomi by saying that he had ordered the hit.

When Celty, Anri Sonohara, and Mikado Ryuugamine arrive to Masaomi's aid and Kadota leads an attack against the Yellow Scarves, Horada flees the scene. While driving away, Shizuo attacks his car and tears the roof off it with a traffic sign in an act of revenge. Shizuo also throws the traffic sign at him, piercing his car like a spear. He makes an escape but in the process speeds in front of Kinnosuke Kuzuhara and subsequently tries to evade him, resulting in his capture and arrest. He attempts to press charges against Shizuo for destroying his car, but to no avail.

Durarara!! SH
As of Durarara!! SH, Horada has been released from prison. He and his goons spill juice on Shizuo and get beat up again.

He and his lackeys attempt to assert their seniority over the current Blue Squares, but Horada backs off after finding out that the current leader, Aoba Kuronuma, is Izumii’s younger brother.

Upon hearing word that Yahiro Mizuchi had managed to stand up to Shizuo in a fight, Horada seeks to recruit him. He begins tailing Himeka Tatsugami in order to use her to get to Yahiro, but ends up witnessing her abduction instead. Some of his men manage to tail the kidnappers back to their base, and Horada passes the location off to Aoba and Yahiro, effectively putting Yahiro in the Blue Squares’ debt.

Horada is later attacked by two of the attackers on passersby and hospitalized. In order to clear up rumors that he had been the attacker, Izumii pressures Horada into finding the real suspect.

Shizuo Heiwajima
Put simply, Horada and Shizuo have an extremely negative relationship. Horada was beaten up by Shizuo on two separate occasions and Horada shot Shizuo. Shizuo then proceeded to destroy his car, which gets him arrested.