Legally speaking, mayhem refers to the gruesome crime of deliberately causing an injury that permanently disfigures another. The name derives via Middle English from the Anglo-French verb maheimer ("to maim") and is probably of Germanic origin; the English verb maim comes from the same ancestor. The disfigurement sense of mayhem first appeared in English in the 15th century. By the 19th century the word had come to mean any kind of violent behavior; nowadays, mayhem can be used to suggest any kind of chaos or disorder, as in "there was mayhem in the streets during the citywide blackout."
"Hero Slayer" requires defeating 25 heroes, of the sort found in Mayhem Missions, tip missions, the Lord Recluse Strike Force, and a few other places. It can take forever to grind those out if you're just relying on those missions, even with the occasional LRSF thrown in. But someone told me about a really speedy way to get it, and I tested it, and it works. So, here it is for you!
This also offers a speedy route for heroes or vigilantes to get the "Invader"/"Task Force Commander" accolade power if they don't want to have to do all the Task Forces to obtain it. Just get "Bloody Hands," then change to Rogue and get the exploration badges from all the Mayhem missions. (You don't even have to complete them; just go into each mission, get the badge, then exit and drop the mission.) Once you have all of them, you will get "Invader," which will magically change to "Task Force Commander" when you return to Paragon City.
(Sadly, there isn't any similarly speedy way to unlock the equivalent badge for the all-Safeguard-missions contact, Villain Disruptor. You just have to grind those out, though the Statesman (Miss Liberty) Task Force can certainly help.)
Minor note about Lord Schweinzer,he gives random mayhem missions so might end up doing the same one over again if you're not careful. Best to click "Ask about what else is going on" when offered mission then you will get a list that is the same every time and an easier way to keep track.
I'll add in that to get Villain Disruptor, the first two missions of Provost Marchand's arc "A New War" have quite a few villains in them. Set difficulty to -1/x1/no Bosses, tear those missions up a few times, and voila. Maybe not as easy as for Hero Slayer, but still.
Also, if you're interested in speed, you can drop and regain any of the missions to try and get a closer mission door since there are only 4 or 5 total options in Port Oakes. Usually I shoot for the sub in the southern part of the map because you can get the first 4 or 5 missions at the same door. With some luck you can knock out the entire accolade in less time than it takes to finish a single TFC task force.
You use another mission you already picked before. You select that mission when out. It asks you if you want to abandon current mission. You choose Yes. Then select the old mission that became abandonable.
Quick note.. unless you're level 50 you can't get the final paragrine island mission. You can unlock Lord Schweinzer earlier, but unless there's a trick I don't know, you have to be level 50 to get the invader badge without help.
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