Drizz'l in 8-Bit Theater. First, he was humiliated when the "true guardian" he bought turned out to be a platypus. Then, he went without a sword for a good majority of the comic and teamed up with the most incompetent antagonists possible. After he finally assumed leadership of the Dark Warriors, his first plan to quit their royal accounting job was an utter embarrassment. Then he was voted off the team (right after finally becoming leader and running a huge, evil castle) and forced to Heel-Face Turn (sorta) and ended up hating the Light Warriors even more. Then the final showdown he was waiting for was interrupted by a pointless election. Then his plan to kill everyone else backfired. Then the Fiends who mistook him as the one who summoned them from Hell were unable to kill his teammates because of family ties. Then said Fiends were suddenly killed off (again). Then his plan to take over the world using the fourelementalorbs of light came to a quick end when Sarda pointed out that they have no idea how to do that. Then said nigh-omnipotentjackasswizard who did it subsequently mind raped the whole team and forced them to run away. And finally, he is the only Very Real Light Warrior unhappy about being credited with saving the world, probably because he never got to be an actual villain and/or due to the whole stupidity of the situation.
[Y]our penchant for mass murder notwithstanding, people tend to regard you as a BIT OF A TOOL.
It's later revealed that he really doesn't care about killing people, he's just doing it to stay close to his hatecrush. He also very easily could have triggered mass-genocide if he wanted to, but actually works to keep it from happening because Feferi would be upset otherwise.
Eridan becomes a full-on subversion when he loses both the "sympathetic" and "ineffectual" parts in Act 5 Act 2. The crush mentioned in the above line? He kills her as he leaps across the Moral Event Horizon.
Though he switches right back to ineffectual when Kanaya comes back from the grave as a vampire and effortlessly fells him. Like a tree.
Jack Noir starts as this. Later into the story...he's significantly less ineffectual or sympathetic.
Likewise Caliborn comes off as too much of a Stupid Evil brat to be a true threat. And than we see how he ended changing his name to Lord English...
Dr. Kinesis in Evil Plan. His technology gets stolen, the other villains laugh at him, and on his minions' first mission, they bump into a brand new superhero.
In El Goonish Shive, technically, Magus was apparently behind the v-five Elliot incident, and tried to manipulate Ellen within some plot that sounds quite dubious. And is not very good at this. But he's in desperate straits, which isn't even his own fault (unlike Abraham's case). And he's still reluctant to kill a guy who stands in his way even when pushed hard to do it.