Darin MacNamara

Darin MacNamara was the chief antagonist of the Angel episode "The Ring" alongside his brother Jack, he was more into the business side of things than Jack - who was the caretaker of sorts to the slaves they forced into fighting for profit: however he was about as ruthless and amoral as a human being could be without becoming fully demonic as he was totally without remorse for any of the atrocities he committed.

History
Darin, alongside Jack, had created a bloodsport via forcing demons and vampires into gladiatoral battles using ancient wrist-bands and mystic lines that would literally disintegrate any who tried to escape: the two also had an army of thugs armed with electric cattle-prods to brutally beat any that refused to fight, to Darin and Jack they were nothing but slaves and thus were treated as objects rather than living beings - Darin ensured the demons were kept inhuman via giving the reward of freedom to any fighter that earned 21 kills.

When Angel was captured by these psychopathic brothers he refused to fight for their amusement but was powerless against them, though he managed to capture Jack and believed he could use him to force Darin to let him go: believing Darin's love for his brother would prevent him from doing anything rash.

Darin simply shrugged Angel's attempt off and shot right through Jack - killing his own brother and injuring Angel, he then had his thugs electrocute Angel as punishment: however he made a deal with Wolfram & Hart to allow Angel to go free and was not impressed when Angel refused the offer, believing Angel had outlived his usefulness Darin put him in a fight against the ruling "champ" Val Trepkos, who was nearing his 21st kill.

However by the time Angel and Val Trepkos began fighting Wesley had already managed to find a way to break the chains and sought Angel out, unable to find him he was distraught when one of the demons stole the key from him - however the demon was moved by Angel's selflessness (despite not fully understanding it) and began setting the other slaves free.

Back in the ring Darin drifted amongst the crowd of LA elite as Angel and Val Trepkos fought, Wesley spotted him and decided to confront him - as this is occuring Angel manages to overcome Val Trepkos but refrains from killing him and after a moment of instinctively fighting back Val Trepkos also stands down, deciding enough is enough.

As the crowds grow restless Darin is confronted by Wesley, who pulls a gun out on him, Darin simply dismisses Wesley with "screw you" - however the confrontation is disrupted when the demon slaves all erupt onto the ring and run riot, attacking Darin's thugs and several audience members as they revolt.

Darin is shoved into the ring during the confrontation, still holding a mystical wrist-band, he speaks his contempt for Val Trepkos - who he calls a "stupid slave" and brandishes a gun, however Val Trepkos has had enough of Darin's cruelty and simply lifts him up and tosses him out of the ring: as Darin hurls through the air he passes one of the mystical lines and is disintegrated within seconds.