I’m going with one of Belghast suggested topics about Boss fights, the raid that I remember the most is from the Rikti War zone in City of Heroes/Villains.
The Lady Grey Task Force was one of the first Task Force in the City of games that allowed both Heroes and Villains to team up co-operatively. Initiated in the Rikti War Zone the task force was for 8 persons and tasked the players with repelling an alien invasion.
Once started the raid consisted of 5 stages there are two fights that I found challenging and enjoyable. The first is a fight against 4 of the Rikti greatest warriors who has been given names designed to invoke fear into the heart of humans.They are referred to as the riders and take the names War, Famine, Pestilence & Death.
Fighting them starts off easy as you only face one, but the fight changes as the number increases with each encounter, so that in the last battle you end up fighting all four bosses at once.
The central part of the story is focused on the last Rikti Invasion attempt and how the Omega Team (a group of 50 heroes) led by Hero 1, travelled through a portal to the Rikti home-world and destroyed it on the other-side.
However the sacrifice of the original team came at a cost and those thought lost were either killed or captured by the Rikti, corrupted and transformed.
The final fight
The raid ends bit taking the fight right to door step of the Raiding Rikti force who are trying to open a new portal to the Rikti homeworld which could bring through their most powerful warrior.
The project is being overseen by Lord of War: Hro’Dtohz who is the lord of the Rikti military caste, him and his plan must be stopped before the Honoree travels to Earth.
You arrive too late and while you are defeating Hro’Dtohz the portal is activated and The Honoree is brought through. As the name and visuals suggest this warrior isn’t Rikti in nature and is in-fact the thought lost Hero 1.
As you are fighting it becomes clear that despite the Rikti influence there is still some of the Hero left, as the battle progresses the internal struggle becomes apparent. Sadly the mind-controlling is too strong and you have to take the Honoree down.
I leave you with a snippet of the Task Force debriefing:
Let us not mourn for his fall, for even with all the alien science bent to break his will, he fought to retain some of his humanity. Perhaps one day, he can be restored. If that day comes, it will be because of your bravery and valour.
Though tinged with sorrow, this is indeed a moment of triumph, your moment of triumph. For you have fought against all odds and saved all of us, and may now stand with your heads held high amongst your peers.