If Dr. No has a PhD in evil, then Professor Dent must have an MA in Henchman Studies.
Compared to more colorful evil henchman in later films, like Oddjob or Jaws, Dent is pretty plain. Actually Dent, a pasty old white guy who likes to study rocks, would be plain even in a lineup of Wall Street executives against a beige wall.
Dent doesn't have razor-sharp teeth, nor can he crush a golf ball in the palm of his hand. Instead, he arranges for someone else to kill Strangways, he makes crass sexual comments about Strangways' dead secretary, he shoots Miss Taro (or a lump of pillows he thinks is Miss Taro) while she's sleeping, and he puts a spider in Bond's bed. Unable or unwilling to do the job himself, the cowardly Dent delegates the murder of James Bond to an arachnid.
It's not clear what Dent's motivation is for working with No. Maybe the bad doctor gives him a kickback in rocks? Whatever the job's benefits are, the risks far outweigh them. Dent is eventually shot by Bond multiple times, including in the back.
Bond's killing of Dent is just as brutal as the deaths Dent is complicit in. With that scene, Dent's death reveals one of the normally cool superspy's flaws—he's actually hot-blooded, with a penchant for revenge.