As we're well aware, video games and boss battles go together as well as the North and a Gregg's sausage roll, to the extent that it's hard to imagine one without the other.
Therefore it's in the medium's best interest to shake up the formula from time to time to keep players on their toes, and for some titles, this takes the shape of villains stepping over to the side of light and justice (albeit sometimes only temporarily) to help deliver an almighty beatdown on another evildoer who's run their mouth a little too much.
Maybe the foe in question has had a change of heart, or just wants to help eliminate the competition before squaring up to you. Either way, we'll take all the help we can get, especially if we get to control these former villains and utilize all of their forbidden powers.
So let's celebrate how team work really does make the dream work, as once nightmare foes help you deliver dirt naps to other bosses.
8. Virgil's Arkham Assist - Devil May Cry 3
Alongside Noel and Liam Gallagher, the brothers Sparda carry with them one of the longest sibling rivalries known to man, with each slinging enough sass and salt at one another to make Steve Harvey sweat through one of his Family Feud suits.
It seems to the layman that you couldn't find two beings more diametrically opposed to one another, while ironically both sharing the same pig-headedness and love for the ultra-violence, and thanks to their ideals clashing as hard as their swords, both Dante and Virgil will often find themselves squaring off against one another.
That being said, even these bickering brothers know when it's time to pop the toys back into the pram and use said baby carriage as a hammer on the head of true, world-threatening evil, and have occasionally teamed up to lay the smackdown on whatever evil is floating in the toilet bowl this morning.
Take for example the closing act of Devil May Cry 3, where generic plop-head Arkham is busy spouting his world-ending nonsense before Virgil interrupts and offers Dante a hand. Together the duo proves once and for all how truly unstoppable they would be if they weren't arguing over Monopoly rules at Christmas, and utterly embarrass Arkham, even ending things with each brother taking Ebony and Ivory and shooting Arkham in his big swirly hole.
Sure enough, the truce was short lasting but what a power trip this was.