Heroes Winning the War
Mevolent was the leader of his army prior to the events of the series but was eventually defeated after a war that encompassed several centuries. Little was known about him before Kingdom of the Wicked, save that he was an extraordinarily powerful Elemental, a worshipper of the Faceless Ones and led an army of mages seeking to make sorcerers the dominant race of the world.
Mevolent Winning the War
In the second dimension revealed in Kingdom of the Wicked, Mevolent and his forces had won the war, with Mevolent ruling over the entire world. He had many supporters and weapons, notably a greatsword called God-Killer and the Sceptre of the Ancients- both weapons capable of killing Faceless Ones. It is revealed that his forces were powerful enough to destroy the entire continent of Africa, the last to be defeated.
Kingdom of the Wicked
Many Cleavers have joined his side as Redhoods and Sensitives patrol the streets, listening for any rebellious thoughts in the populace. A magical Internet has been invented, with every advance in technology being kept for mages. Only a small Resistance remains, made up the surviving soldiers of the army who opposed him, led by China Sorrows.
During Kingdom of the Wicked, Valkyrie is pulled into his dimension by a Dimensional Shunter. Initially, her only goal is to survive until she is returned home. However, she is captured by Baron Vengeous and thrown into the dungeons by Mevolent. The Resistance frees her with a captured Teleporter, but it is later revealed Mevolent anticipated them and tracked the Teleporter. The Resistance is ambushed and Valkyrie is shunted home.
When she returns to her own dimension, she realises that the Sceptre of the Ancients is the only weapon she can use to stop Argeddion in her own dimension and returns to Mevolent's dimension with Skulduggery. There, they enlist China's help and unexpectedly, that of Nefarian Serpine. They manage to steal the Sceptre, but until either Mevolent is dead or they return home it is useless.
Mevolent leads his army to destroy the Resistance, using God-Killer against Darquesse. She tries to kill him by telekinetically destroying every bone in his body, but he simply repairs himself and attacks her. A huge, violent fight breaks out between the two of them, and they both seem evenly matched - they can both fly, and even after Mevolent rips her head off, Darquesse repairs herself and continues the battle - until Darquesse manages to temporarily stun him, almost killing him before she turns back into Valkyrie. China almost steals the Sceptre of the Ancients, but is killed by Serpine. When Valkyrie is shunted back home, she thinks the Sceptre is still back in Mevolent's dimension. In reality, she just did not notice it coming with her.
Mevolent is still at large and may appear in a future book, due to him being able to use the Sceptre of the Ancients as an Isthamus Anchor.
Mevolent has the abilities of an Elemental. He can manipulate Fire, Water, Wind and Earth. Possibly the most powerful Elemental since the Ancients, the limits of his powers are unknown. Mevolent also has powerful magical artifacts such as God-Killer, a sword that can cause wounds which dont heal and the Sceptre of the Ancients, a staff capable of turning anything its ray touches into dust. He is capable of flight due to his mastery of air. He can also, through unknown means, repair bones, organs and arteries of his body if they are broken or destroyed. Mevolent was also incredibly strong, as he was capable of ripping a person's head off with only his bare hands.
Mevolent is a loyal follower of the Faceless Ones, believing his gods to be the rightful rulers of the world, and that sorcerers should be their servants. He despises anyone who refused to serve under him, and follow the Faceless Ones, to the point that all the warlocks have been extinct due to that, and mortals all over the world are treated as inferior slaves. Despite his rather violent and cruel personality, Mevolent can be quite charismatic when he wants to be, able to reunite several sorcerers around the world, such as Baron Vengeous, Nefarian Serpine and several others, under his leadership, and wage war against the sanctuaries.