- "The good... they do not know how close to evil they really are..."
- — The Second Overlord.
The Second Overlord was one of the greatest Overlords known to have existed. It is unlikely, however, that he is actually the second successor in the lineage.
Indeed, according to Gnarl, he has seen at least four masters destroyed. It is possible, but unlikely, that he includes the so-called "Second Overlord" in his list while excluding the 8th Hero, who was trapped alive within the Infernal Abyss.
It is not known what the Second Overlord may have looked like, where he came from or who he was, although it has been suggested that he is the Overlord from Overlord: Dark Legend, considering they both have Gnarl at their side along with the Jester and Tower Heart. However, if he is the Overlord from Dark Legend, then it is unknown why he left Castle Gromgard for The Dark Tower. It is possible he may have found it, his uncle told him where it was, or Gnarl led him there. Furthermore, due to a similarity in design, Castle Gromgard itself may have been converted into the Dark Tower.
This Overlord was supposed to have been the formal leader of the minions and the embodiment of evil, until the Seven Heroes came along, and the 8th Hero grabbed him and jumped off the Dark Tower, killing both of them. However, the Overlord cheated death by taking control of the Wizard's body and driving his soul into oblivion.
He then made all the heroes fall victim to their own personal vices, causing each to represent one of the seven deadly sins, and sent a contingent of Ruborian Raiders to besiege Castle Spree. After those changes, the 8th Hero was resurrected as the Third Overlord, who killed five out of the seven heroes (excluding the Wizard) and captured one. The Third Overlord took control of the Second Overlord's tower and minions with the help of Rose or Velvet.
This led to a "Minion Civil War", which ended when the Second Overlord was killed by the Third Overlord.
However, it has been hinted that the Second Overlord possessed the Jester after his death; this would explain why the old Jester is missing from the second game. And why his silhouette was shown in the final abyss portal just before it exploded, trapping the Third Overlord.
The old Overlord was very evil, powerful, and intelligent. However, for all his strength, even he could not stand against the combined might of the Eight Heroes. Despite this, he was able to quickly turn the tables by possessing the Wizard and manipulating everyone in his grand scheme to reclaim everything that was his. He is extremely arrogant and prideful, viewing everyone as mere pawns to be used.
His dialogue reveals he is also quite perceptive and insightful: Not only was he able to easily corrupt the heroes by playing off of their vices, but he also relates good and evil quite closely, seeming to think of them as two sides of the same coin. Alas, in doing so he could not see that he himself had fallen victim to the most dangerous vice of all - his own pride.
His was blinded from his normal insightfulness, not seeming to realize the extent of his own pride or the chance of his plan's failure. It also stopped him from seeing the threat posed by the 8th Hero. Even though he had defeated him the first time, the old Overlord healed him and made him his temporary successor, allowing him to gain even more power - this would ultimately result in his second and permanent downfall.
Nothing is known about his time as Overlord other than being the arch-enemy of the Wizard. He may have been one of the most evil of his kind, as the Heroes were worshipped after beating him, with Melvin and Goldo even being made kings. He had an unusually hands-off overlord style - despite being able to summon more minions at once than any other overlord yet seen, he did not take direct control of them and preferred to send them out while he stayed out of the line of fire.
This should not be mistaken for cowardice, but another example of his pride. He saw his enemies has beneath him, and because of this the Minions under his command were not well organized - acting in small scattered groups instead of one united horde, with little to no teamwork between the different minion types. Also interesting to note is that the Blue minions did not appear during the "Minion Civil War", emphasizing his hoard's inability to support itself with a lack of healing posts.
He also loved to hear himself talk, rambling on about his corruption of the heroes and how good and evil were so close. Even as he fell defeated, he cried out about how the good don't know how close they are to evil and even after falling will continue to repeat the lines about how he corrupted the heroes within an endless loop until he is dead.
He shows off a number of powers, including a shield spell, a tornado spell, and even uses magic to break down a wall. It is unknown if these spells are the Wizard's or his, perhaps even both. He also had control over many Green, Red and Brown minions, though he is not as skilled at controlling them than most other Overlords - this may be a result of him missing the Third Overlord's gauntlet.
After regaining all the minion hives, the Third Overlord meets the Second Overlord down in an arena connected to the minion hives. Blasting the wall back into place, the battle for Overlord supremacy begins.
The Second Overlord will move and surround himself in a colored bubble, summoning a force of his own minions every time. The way to break his barrier is to send similar colored minions towards him, and he will be rendered vulnerable for a few moments. After losing a set amount of health, he will teleport away. In this time, the Third Overlord will find himself surrounded on all sides by enemy minions. After that, the fight proceeds like the first half, only now between magic shields, he will turn himself into a destructive tornado and blast around the arena. One of the safe zones is back at the entrance. Upon defeat, the Second Overlord will crawl on his hands and knees to the middle of the arena to be defeated once and for all by the Third Overlord.
During the battle, he will repeat his triumphs over the 6 heroes endlessly, even on death's door.
"Have another roast pig Melvin...have two...you're a Hero now."
"Have a rest Oberon, heroes need their rest."
"I think she likes you Sir William, if you want to slip away with her, I won't tell anyone."
"Goldo you can have all the gold you've ever wanted, my friend! No one would refuse a hero."
"That Jewel had everything, it turned out what she wanted was what other people had."
"Hard to see what you love taken away, isn't it Kahn? When reason is gone, nothing is left but madness!"
- It is possible that the Overlord doesn't have complete control over the Wizard's body, because of him referring to Velvet and Rose as if he knew them personally before. He is likely influenced by the Original Wizard's soul having some kind of control, or simply retains some of his old memories. He can also use spells not related to an Overlord (via Tower Objects) such as creating Tornadoes and Levitating, proof that those spells possibly belonged to the Wizard.
- The tower's background becomes darker when the Second Overlord returns, likely because of overwriting the corruption of the tower to his evil energy type. However, this section of the story could also take place during the night.
- It's also possible that there have been numerous Overlords between the first and second Overlord that we don't know about.